I love them. They have been my all time favorite band for several years. They're the artists who got me into "good" music and made me download full albums, research about music, get to the essentials and eventually discover /mu/.
My favorite album by theirs is Kid A, with In Rainbows coming only half an inch after.
My least favorite is Pablo Honey, although I don't feel like it's THAT bad. You, Creep and Blow Out are pretty amazing songs.
IMO they're the best band currently producing music and I get fucking hyped for every release they make.