Bruce Springsteen: Darkness on the Edge of Town
U2: The Joshua Tree
U2: Wide Awake in America
U2: Boy
Pearl Jam: Vs
and I plan to get quite a few more, which I'll probably post below since they're some of my favorite covers. Albums are artwork in more than just one way, and an appealing cover can open a door into an entire discography of an artist if it catches your eye. That being said...which covers really draw you in?
My favorite U2 ones are War, All That You Can't Leave Behind, and The Joshua Tree.
We can probably start with the obligatory "Dark Side of the Moon" and just knock that right out of the way, I think.
Otherwise...
Blink 182: Enema of the State

I really love the blue tone of the entire cover, and who could lie- the sexy nurse ready to let go of that glove

The Black Keys: Brothers

Need I say more? They certainly didn't.
Smashing Pumpkins: Siamese Dream

I can't really explain why I love this one...could be that the album is such a 90's icon in itself that I just associate it with that music and that's why I'd be so fond of it on my wall.
Green Day: American Idiot

Just cool.
The Rolling Stones: Sticky Fingers

A classic! The contrast on this one seems to be jacked up so the bulge is a little harder to see, but it's a funny and classic cover none the less.
These are just a few, and the most stand-outs of my all time favorites...There are so many other subtle ones that really do the trick as well, I could go on for pages and pages. Just wanted to get the ball rolling though.