SDOIT and SFAM are my favorite artworks, but i enjoy most of them
I despise most of them:
WDADU - just gross
I&W - dat kitsch
Awake - same as above, but with redeeming factors (color scheme, all the songs represented)
ACOS - WTF?
FII - too bad for the font, otherwise a really good one
SFAM - love it, mostly because it reminds me of the classic prog rock covers
SDOIT - pleasant looking, but reminds me of baseball caps, loose jeans and skateboards...not a good fit for DT.
ToT - As Eye Am
Octavarium - good concept, sloppy execution. The grass looks like it's from Fifa '98 and the whole thing has a late '90s video game quality to it.
SC - looks cheap in some places, bad font, but kinda like the comic book style
BC&SL - the kitsch is back...and the elephant from 3dmark 2003...
ADTOE - this one is refreshing to look at. I like the colors, tooone and the simplicity (most DT covers are overcrowded)