Recently I installed Angry Birds in my HTC Desire S. It was awesome if I don't exaggerate. Level designes were well balanced - not too hard or not too bland. Plenty of levels were provided in the game to keep a player engaged for a long time.
Since, it came in many platforms, casual gamers must play this game on their choosen platform.
I've also played Angry Birds: Rio and Seasons which reached the same height of the original game.This game is solid and never crashed in my mobile. Try it out and you won't find it bland.