I like too many....and I love this thread, so I'd like to add some that I can remember right now:
in no particular order
"Love In vain" by The Rolling Stones
"Born Under A Bad SIgn" by Cream
"Born Under A Bad Sign" byJimi Hendrix
"Que Sera Sera" by Sly & The Family Stone
"It's All Over Now" by Johnny Winter
"She's A Woman" by Jeff Beck
"Oh Pretty Woman"by Van Halen
"Everytime You Go Away"by Paul Young
"You Can't Hurry Love" by Phil Collins
"Time After Time" by Miles Davis
"Can't TakeMy Eyes Off Of You" by Lauryn Hill
"Feel Like Makin' Love" by D'Angelo
I like when the cover: achieve more of 'something' than the original, or even more known/familiar than the original...or if it 'bravely' broke the boundaries of arrangements, far different, unpredictable etc, that might be risky or controversial, but at the same time (at least try to) explores more creative atmosphere than it's legacy...whatever it is, whether they're succes or fail with the result
'Copy cat' -note to note the same as the original- type of cover work, usually doesn't impress me.
YMMV