What are some really good apps to download for your ipod/iphone?

I'm getting another ipod for Christmas and just want a few ideas of some apps that are good.

Added (1). Mostly gaming apps

What kind of apps? Gaming apps, music apps, learning apps? More info please

There are a lot of good games for iPod like Christmas Games, action games, strategy games, creativity games, leisure games, sport games and so on. You can choose the games from the below link.