well, personally, i find the best thing about the game is how massive the world is. u really have to go everywhere to appreciate it. the quests are a bit lame imo, and the story is too short, but i think the whole dc wasteland is worth it.
unfortunately i believe you have the 360 version, so you cannot download mods, etc, to get even more out of your game. if you see how many mods are out there you will be amazed, and even more have been coming out recently with the release of the developer kit, which i belive is called the GECK