Seriously, guys? Appeal to Reason is NOT that good of an album. Try listening to The Sufferer & The Witness or Revolutions Per Minute and you'll see why.
I would say the best album of 2008 is by far Jason Mraz's We Sing. We Dance. We Steal Things. So much versatility, and he's a natural songwriter and singer.
No denying that their old music was awesome, and that Albums like Ride the Lightning, and ... And Justice for All were great, but compared to their other recent material, and considering that no band will stay young forever, or that any band can play the same thing forever (if they continually played the same music, you would be bored with it, and they would have died away years ago.)
I would say that DM was a pretty good album. It had its fair share of decent tracks, including a pretty good instrumental (no Call of Ktulu, but its not bad.)
Here's a few 2008 albums that definitely deserve mentioning:
Leviathan - Massive Conspiracy Against All Life Helios - Caesura Nadja - Christ Send Light Nadja - Desire in Uneasiness Nadja - Skin Turns to Glass (rerecord) Gridlink - Amber Gray Have a Nice Life - Deathconsciousness Lantlôs - Lantlôs I Shalt Become - Requiem Ghostlimb - Bearing and Distance
I'm sure I've forgotten a few, but the ones I've listed are fantastic.
I really can't think of anything good. If I can have a little leeway time wise I would say sgt peppers lonely hearts club band or Live at Leeds by The Who.
My vote goes to Oasis for Dig Out Your Soul. A great return to form for the ultimate BritPop band.