Generally, I hate the long, drawn-out sessions of a PbP or PbE adventure or campaign. It is tedious, it takes ages to complete one adventure, let alone a campaign and sometimes, players or GMs drop out somewhere in the middle. For inplay sessions, forums or mailing lists are fine, but in my opinion, not for real play. It's a matter of preference, though.
Me, I don't even have a RL group anymore
Instead, I play over IRC, with a dicebot in a chat channel. It's real-time, cuts down on ooc-chatter (there usually is a lot of it in RL games, and I am not innocent of adding to this

) and gives easy access to log files. For sketches and floor plans, I use
http://scriblink.com/ and it works out pretty well, most of the time.
The sessions tend to take a bit longer than a game at a table, so I give 1 Karma per session for ongoing motivation