I love Iphone games. They're so simple in design but so fun to play. Apart from the top 3 mentioned, some other top games are:
- Plants vs. Zombies (multi lane tower defense)
- driver (great psx port, with added radio)
- Hawx (nice port, grahics are nice
- Knights Onrush (castle defense game where you can throw your attackers around, sacrifice them to dragons, kill them with fireballs etc)
- Starwars the force unleased (swipe a certain way to perform force powers, kind of like black & white)
- Conquest (risk clone)
- Osmos (move by expelling mass, absorb things smaller then you, if you move, you expel mass thus become smaller)
- Game Dev story (management game about making your own game studio
- Geodefense swarm (maze tower defense with nice vector graphics)
- Skysiege (Augmented reality shooter with helicopters and rocketlaunchers)
- dr. Awesome (kill diseases by cutting them apart, patient's names are taken from your contact list)
and last but not least: Pocket God (sort of a God sandbox game, with alot of minigames hidden inside it, like doodle jump and FallDown)
Dl;dr: Iphone games are awesome.