At the minute I would have to be 'beautiful day' for me cos I only have my laptop to listen to music on. If I had a decent set of tweeters and a sub it would probably be 'I still haven't found what I'm looking for'.
Definately Beautiful Day, Sweetest Thing and also U2 vs LMC - Take Me To The Clouds Above - not really U2 at all but still a great tune, and uses their samples so still counts.
*stabs frenziedly*
age hasn't got anything to do with it, it's called bothering to find out for yourself what else a band has done. It's not like U2 are anything like obscure...