While I think cover bands are lame, I am fond of the odd B-Side cover. Here are some of my favourits:

Burn in hell (Twisted Sister) - Dimmu Borgir
God of Thunder (Kiss) - Entombed
Massacre (Thin Lizzy) - Iron Maiden
Over the Hills (Gary Moore) - Nightwish
I just died in your arms tonight (cutting crew) - To/Die/For
I love the dead (alice cooper) - Samael
The Wild Rover (traditioal) - Tyr
Joleen (Dolly Parton) - Sisters of Mercy

Gimmie Shelter (Rolling Stones) - The Hellacopters

Message in a Bottle (The Police) - Machine Head

Hurt (NIN) - Johnny Cash

Personal Jesus (Depeche Mode) - Johnny Cash (Well, about every cover of DP's songs enhances them.)

One (Metallica) - Apocalyptica

Bullet the Blue Sky (U2) - Sepultura

Blue Monday (New Order) - Orgy

No Quarter (Led Zeppelin) - Tool and Cowbar

War Pigs (Black Sabbath) - Faith no more

War, what is it good for (Edwin Star) - Bone, Thugs 'n Harmony with Henry Rollins

Paint it, black (Stones) - Gob

Stray Cat Blues (Stones) - Soundgarden

Come together (Beatles) - Soundgarden

Hole in the Sky (Black Sabbath) - Pantera

Foy Lady, Purple Haze (Jimi Hendrx) - The Cure

Killer Queen (Queen) - Travis

Disco 2000 (Pulp) - William Shatner with Joe Jackson

Have a Cigar (Pink Floyd) - Foo Fighters


Can't remember more.

Did I mention that I collect cover versions? :D

Emerald (Thin Lizzy) - Skyclad
Diamonds and rust (Joan Baez) - Judas Priest
Green Manalishi (Fleetwood Mac) - Judas Priest
The real me (Who) - W.A.S.P.
Wishing well (Free) - Gary Moore
Father of day, father of night (Bob Dylan) - Manfred Mann's Earth Band
Saturday night special (Lynyrd Skynyrd) - Armored Saint