I think P2P will definitely have some uses. I am a member of gPulp (http://gnutellang.wego.com
) which is an open group that is investigating different P2P architectures along with improving the Gnutella protocol. For certain business or economic operations - especially internet based, the architecture can be quite compelling. For example, the auction model consists of a consumer connecting to a broker and after negotiation the broker delegates the conversation to a service provider for completion of the transaction. Aspects of P2P can be useful in this model where the broker is acting as a smart router.
I know HP has done some very interesting work in these areas with E-Speak (http://e-speak.hp.com