The question really comes down to:
Do you want the burden of configuring the host networking (routing, discoverability, availability, etc) to fall on you (client server) or on your users (peer to peer)?
This is rhetorical
client server is the way to go.
P2P is hell to support, and users often have a lot of trouble getting it to work.
http://games.joshkirklin.com/sulium
A single player RPG featuring a branching, player driven storyline of meaningful choices and multiple endings alongside challenging active combat and intelligent AI.
