"Closer" Nine Inch Nails (that one has been stuck in my head since 94, don't know if "catchy" is the word for it, though)
someone said "idioteque" from Radiohead already, right? There's a song by them called "How Can You Be Sure?" that I also find extremely catchy.
many songs from R.E.M.
"Country House" Blur. Actually, many songs from Blur.
"Anthem for a 17 year old girl" Broken Social Scene (The chorus sticks with me long after I've stopped listening to it. Don't know why. I'm not a 17-year old girl)
Anyway, there are a lot of others, I just thought of those.
For some reason, whenever I listened to "Svefn-g-englar" by Sigur Rós, i'd have the "tju tju" chant-moan-whatever-it-is stuck in my head for the rest of the day. I'm cured now, after listening to it about 7 billion times.