My recommendation is Bejeweled 2.

I've been playing it for like 6 months now...

I have a love hate relation with Popcap, - i love them for making some of the most addictive games ever and i hate them for sucking up so much of my time

I'm surprised this hasn't been mentioned but if Tap Tap Revenge is on the list, then Tap Tap Dance should go on as well. Diverse selection of licensed 'dance' music and because dance music uses a standard 4 beat template, lends itself to a gameplay style that makes more sense. Even if the shaking your iphone bits tend to more often than not break your rhythm. Still the interface is a lot better than the original tap tap revenge with the psychedelic lights being a major highlight.

Sadly iphone games go in the iphone games subforum - and it's impractical to have 1 forum thread per title since there are like a gajillion titles so it gets consolidated into one thread.