Cheap, accessible, good looking and fun to play. Everything you would want in your usual IPod Game.
The mighty Behemoth that is Angry Birds has been kicking for a while and for all a good reason. it's one of the best App games on the iTunes marketplace. Lots of free DLC, which is what a lot of developers don't do usually. Accessible gameplay in which you throw Angry birds into weird green pigs (Or piglets) and crushing their buildings around them, theres nothing much to the gameplay yet its simple, fun and addictive. Graphically, clean simple and sweet.
On the downside of Angry Birds there is little of variation, you kinda so the same thing over and over again just in different areas, it's not necessarily a bad thing when the gameplay is quite good, but just a minor setback. One nuisance however is that sometimes the framerate's drop when a lot of structures are being destroyed at once. it's noticeable, but its not game breaking or won't hamper your fun regardless.
Possibly one of the best apps on the iTunes marketplace, if your the small minority who have not been playing it, you will find a wealth of content for your money here.