If anyone's interested, this[1] paper highlights why P2P, especially in gaming applications, isn't going away any time soon. Unfortunately, P2P authors really need better systems to keep inter-AS traffic to a minimal level, but the current Internet wasn't really designed with that in mind. There are a number of different research efforts and fielded methods out right now, but none seem to have taken a really strong hold.

[1] http://research.microsoft.com/pubs/72879/donnybrook.pdf