Comical ones are William Shatner...Lucy in the Sky with Diamonds, and recently(ish) Pulps Common People
Ones to avoid are 99% of boy/girl bands that must just go through the Big Bumper Book of 70s, 80s and 90s hits and then murder it...even if its for charity its still annoying
McFly - Dont Stop Me Now
Girls Aloud - Stand by You
Atomic Kitten - Eternal Flame, and Tide is High and many more
Boyzone (Ronan Keating), Westlife - far too many too mention
99% of X-factor, Pop Idol, Fame Acadamy people who covered and then released songs
Phew....
Good ones...Yep already been mentioned Jeff Buckley, and Johnny Cashs version of Hurt are 2 that are favs of mine
Also The first Cut is the Deepest has been covered a good few times, and I havent heard a bad one yet
Knocking on heavens door and Live and let die were ably covered by Guns and Roses..but still prefer the orginals