Ok , I am a lineman at Comcast, most users do not even come close to the 250GB cap, most ISP's have bandwith caps, you just dont hear about them, most ISP's monitor ports, mainly Peer to Peer, they want to make sure your not using most of the bandwith downloading illegal movies and music. In my house I have 3 XBOX's , 2 for my kids, 1 for me. Also, we have at least 3 PC's in the house, all mostly being used for gaming. My son is constantly downloading patches and things for his Warcraft, and Im always downloading game maps from our servers. One month I got to 185GB with heavy usage.
Shamu, you really wouldn't gain anything upgrading to that tier, is over kill for users like us. Better for alot of data transfer users, not really for gamers per say.