For iPhone, I would recommend...

Super8 - Retro 8mm video recorder
Zephyr - UI enhancement to bring swipe and better multitasking to iphone (gotta jailbreak though)
Splashtop - Low Latency remote desktop with gesture support
Epic Citadel - Game Demo eye candy
GTA3 - just because it's GTA

Can't think of anymore without my ipod to hand, but they are my faves from the top of my head.