In Rainbows is growing on me, but by far my favorites are Hail to the Thief, then closely followed by OK Computer. Amnesiac takes third. I have but don't really like Kid A, The BenRAB, or Pablo Honey. They are ok, but not RH's best imo, but what do I know, my favorite band is Foo Fighters .
Top recent albums for me:
2008 Opeth - Watershed
2008 Enigma - Seven Lives Many Faces
2008 Coldplay - Viva LaVida
2007 Foo Fighters - Echoes, Silence, Patience and Grace
Any of these 4 I could play for weeks on end on repeat without a problem at all.