Best head-to-head games for iphone?

Hi,

Could someone point out what the best multiplayer games are for the iphone? I'm looking for games that can be played head to head, like fruit ninja's.

If there is a super puzzle fighter or even a tetris like game where blowing up a gem or clearing a line will add a line to the other player, that would be cool.

I'd prefer to play online over the internet rather than being limited to bluetooth or wifi only.

Thanks!