Mostly DnD but I have limited experience with D20 Modern, Vampire the Masquerade and Traveler (a space themed d100) and a Final Fantasy hybrid that was off the net for a few years.
Yes I'm in a group, I used to be in two but was eating up a lot of time.
I'm not actively DMing (my group passes around so it's not my turn.) But I do DM and I'm currently putting together what will be my next one but it's a pain because I I suck at drawing maps and I need a pretty detailed one for this.
Sean - for big maps, I know you've heard of campaign cartographer, but there's also an open source program called AutoRealm, I've never tried it but you might wanna check that one out.