One can only wonder what Thom Yorke and his band mates will make of Exit Music: Songs with Radio Heads, the tribute album to Radiohead that is released on Monday. As an outfit who have consistently exhibited a marked disinclination to reprise past glories in favour of prog-rockish adventure, you suspect that they aren't thrilled at the prospect.
Similarly, were the ghost of Serge Gainsbourg to be aware of the recent Monsieur Gainsbourg Revisited, he might well be turning in his grave. Ever the sonic sophisticate, Gainsbourg's sometime excellent pop confections were habitually infused with ironic distance from the musical forms he plundered.
So, to hear the usually excellent Cat Power and Karen Elson revisiting "Je t'aime, moi non plus", is to experience more than a little ennui. Still, MGR boasts a better-than-average line-up, including Michael Stipe, Jarvis Cocker, Tricky, Franz Ferdinand and, of course, Jane Birkin. But why do they do it?
Traditionally, tribute albums have tended to enjoy about as high a standing as the novelty song. Anyone looking for a reason why could try listening to, say, Tower of Song: the Songs of Leonard Cohen, a wretched 1995 collection. If you're tempted by Don Henley emoting on "Everybody Knows", Sting declaiming loftily on a decimation of "Sisters of Mercy", Bono slaughtering "Hallelujah", and Elton John doing a hideous hit-and-run job on "I'm Your Man", be warned: you are about to enter a world of pain.
And there's more where it came from. The tribute-albums industry devoted to the Beatles includes records in bluegrass, a cappella, loungecore and reggae (Mellow Dubmarine, no less) stylings, and it's growing so quickly that there can be few Beatles songs left uncovered.
Ditto Led Zeppelin, whose hangers-on have released albums such as The Song Retains the Name (but not a lot else) and This Ain't No Tribute (oh, yes it is). You'll also find hundreds of hairy-metal horrors, devoted to the likes of Priest and Maiden, as well as shrines to more cultish outfits (The Cure, The Smiths).
Some recent offerings, however, have raised the bar. Por Vida, a collection of songs by the multi-faceted American singer-songwriter Alejandro Escovedo, earnt itself favour by raising funds for its subject's health bills, the man himself being ill with hepatitis C. But it proved just what a wealth of material Escovedo has written, and saw many of its contributors excavating it sensitively, from John Cale's rueful "She Doesn't Live Here Anymore" to an acute collaboration from the alt-country trio of M Ward, Howe Gelb and Vic Chesnutt.
Other tribute albums that transcend the genre include The Late Great Daniel Johnston: Discovered Covered, on which talents as fulsome as Mercury Rev, Tom Waits and Bright Eyes pay tribute to the American underground legend Johnston.
Or there's Dream Brother, a bold combination of songs by the ill-starred 1960s singer-songwriter Tim Buckley and his no-less-ill-starred son, Jeff, with contributors ranging from the Magic Numbers and Sufjan Stevens to nu-folkies such as Adem, and folktronica avatars such as Tunng.
If I Were a Carpenter is a successful take on Karen's and her brother's back catalogue by a respectful slew of 1990s American alt-rockers, opening up their work to an audience who might otherwise have been sniffy about it. Karen Carpenter obsessives Sonic Youth's "Superstar" is sublimely straight-faced, and Mark Eitzel flexes his emotive chops on American Music Club's gorgeous cover of "Goodbye to Love".
But why hasn't the tribute album always looked so good? For starters, fans of the artist being worshipped will be more interested in the originals than cover versions, while fans of a band on the album will probably be hitting "skip" over the other contributors. The results are often stultified with reverence for the artist being covered, or a conviction that they can improved on.
The impetus behind Tower of Song, say, seemed to be that Cohen's originals could be bettered with more elaborate vocalisms. The results simply proved that Cohen's understatement preserves a simultaneous sense of personality and mystery in his songs that the never knowingly understated Bono and Elton cannot.
A similar fate befalls a mixed mess of talent on Sweet Relief II, a tribute album devoted to the cracked country songs of the singular Georgia-based singer-songwriter Vic Chesnutt. Kristin Hersh and the alt-country demi-gods Sparklehorse make sense on there; so do Garbage, surprisingly, whose cover of "Kick My Ass" is the finest song Shirley Manson and co have associated themselves with.
But why are corporate try-hards such as the Smashing Pumpkins, Madonna and Hootie and the Blowfish on it? Were they perhaps going after some of Chesnutt's authentically left-field flavour?
A Tom Waits tribute album, Step Right Up, saw another set of hapless contributors struggling to reshape an icon in their own image. Granted, the late Gun Club mainman J Lee Pierce makes Waits's "Pasties and a G-String" sound as ravaged as anyone might care to hear; but the rest of the covers wilt next to Waits, from the Tindersticks' dreary "Mockin' Bird" to Jonathan Richman's limp "Heart of Saturday Night".
An earlier Tim Buckley tribute album, Sing a Song for You, fell flat for similar reasons. Low-level personalities such as Tram and the Lilys cowered like rabbits in the headlights of Buckley's legacy, too timid to attempt anything more distinct than weak approximations of the legend. Only Mark Lanegan managed to do credit to Buckley and himself, with a sublimely sad rendition of "Cafe".
That brings us to Dream Brother, an album that strikes a fine balance between honouring the Buckleys' songs, interpreting them and establishing its own personality. Inspired by the music writer David Browne's book of the same name, its mixing of songs by father and son is bold in itself: Jeff avoided comparisons with the father he barely knew, and it seems crass to compare them solely on the grounds that both died young (Tim at 28, Jeff at 30).
But there are other, legitimate reasons to couple them, as Browne argues. "They both had a sort of stick-it-to-the man approach and were not songwriters who would write with hit singles in mind.
"It sounds corny, but they approached music as a kind of pure transcendence in expression, this elevating force you tap into. Both had ambivalent feelings about the music business. It goes beyond the fact that they both died young."
Similarly, the talents involved in Dream Brother don't have a huge chart career in mind: they're properly left-field, idiosyncratic voices, coherently assembled from (broadly speaking) nu-folkies who share a refreshingly idealist anti-commercialism.
On Jeff's "Yard of Blonde Girls", a typically stripped-back Micah P Hinson doesn't attempt Buckley Jnr's falsetto, but sticks instead to his own older-than-his-years bark.
The Magic Numbers make light of Tim's "Sing a Song for You", Tunng disassemble previously guitar-based arrangements, and the Earlies (who are self-proclaimed "Northern scrubbers") bring a dash of delicate space-folk trancendentalism to Tim's "I Must Have Been Blind".
As the latter's Giles Hatton says: "It is different but I think we did a respectful job. We wanted it to sound like us but I don't think that we shat on his memory."
In its own way, to do anything that wasn't different would be to besmirch Tim Buckley's memory. His daring career saw him progress from folkie to atonal jazz adventurer. Love Buckley Sr or not, he took risks.
"When I heard this album, I didn't recognise half the songs," says Browne. "That's a tribute in itself, because the Buckleys never took the easy way out. For people to have their way with the songs and not do simple cookie-cutter remakes is in keeping with their spirit."
Would Tim or Jeff have liked it? It is impossible to say, but at least you can says thatDream Brother isn't overshadowed by the Buckleys' own tower of song.
The five best...
If I Were a Carpenter (A&M)
Irony gives way to strait-laced interpretations that bring out the troubled heart of Karen and Richard Carpenter. American alt-rock types such as Sonic Youth, American Music Club and Grant Lee Buffalo opened up the back-catalogue to a new audience.
I'm Your Fan: the Songs of Leonard Cohen (Warner)
Not perfect, but worth it for one or two stand-outs, such as John Cale's resonant "Hallelujah" and Pixies' "I Can't Forget", which may even - whisper it - improve on the original. Alas, James and Nick Cave slaughter their respective efforts.
I am the Resurrection: a Tribute to John Fahey (Vanguard)
The alt-folk stalwart M Ward proves sympathetic to the pioneering spirit of Fahey. Choice cuts: Calexico's wiry workout, Sufjan Stevens' dreamscape and Ward's own rollicking interpretation.
Return of the Grievous Angel: a Tribute to Gram Parsons (Almo)
Parsons' long-standing influence on all things alt.country receives the appropriate doff of the cap. The Lemonheads' Evan Dando covers "$1,000 Wedding" beautifully.
The Late Great Daniel Johnston: Discovered Covered (Gammon)
The troubled underground icon receives due homage from the cream of American alt-rock. It features a collaboration between Mark Linkous of Sparklehorse and The Flaming Lips. Unmissable.
...And the worst
Material Voices: a Tribute to Madonna (Delta Deluxe)
Several 1980s outfits re-emerge to kneel before Madge. Gene Loves Jezebel do "Frozen", Berlin take nobody's breath away with "Live to Tell" and Sigue Sigue Sputnik pummel "Ray of Light" senseless. Thank your lucky star if you've never heard it.
Tower of Song: the Songs of Leonard Cohen (A&M)
It's a tower of something, all right, and steaming with it. An ill-fitting cast of contributors, including Billy Joel and Bono, over-emote on some of Cohen's most beautifully understated songs.
Shöut at the Remix: a Tribute to Mötley Crüe (Cleopatra)
From the first umlaut down, the accent is on off-the-scale badness here. The track-listing contains the dread words "Sigue Sigue Sputnik remix".
Urban Renewal: the Songs of Phil Collins (WEA)
The clown king of cheese receives the attention of hip-hop's head honchos, from Lil' Kim to Ol' Dirty Bastard, who prove that you cannot build on Collins's fetid swamp of song.
Killer Queen: a Tribute to Queen (Avex)
Shinedown (who?) and Antigone (double who?) are among those giving faithful, aka horrid, retakes on what is really a PR exercise for the We Will Rock You musical. The Flaming Lips' "Bohemian Rhapsody" is the sole survivor here.