I've been playing RPGs since the early 80s, starting with AD&D1e and Moldvay Basic and growing outward from there. I've had a Palladium phase, a GURPS-only phase, and a disposable income phase in which I bought nearly every game I found remotely interesting. Now I'm in that mid-life crisis phase where I've sold off a few games but still collect when I can, and think about playing far more often than I'm actually able to game.
I'm primarily a GM, though I do enjoy playing from time to time. I also get many more ideas for games than I can possibly run for my own group, so I wouldn't mind an arena to test out some of them. I don't have children, but I am married and my ever-changing work schedule makes a regular game difficult at best.
I'm most comfortable with iterations of D&D from Basic/Expert to 3.5, GURPS 3rd & 4th Edition, and Basic RolePlaying. Having said that, I'm familiar with a lot of games and am willing to try running almost anything in my library. The most recent games I've played were Dragon Age, The One Ring, and a FATE adaptation of CthulhuTech.
As a player, I'm interested in roleplaying a character. Having the best stats or raking in the most kills aren't really priorities for me. I am happy to fill in gaps in the party, playing the Cleric or the Decker or whatever niche is needed; I'm also happy to take over an NPC in order to join an already-established group. So long as I can interact in-character, taking on a different persona, I generally will have a good time.
As a GM, my primary interest is in making an interesting backdrop for the PCs' adventures. I have been leaning more toward the sandbox style of play lately, offering numerous options for adventure that PCs can seek out, though I'm not above introducing overarching plots. I try to embrace the "Yes, and..." style of improv, doing my best to avoid railroading. I also try to incorporate PC backgrounds, connections, and so on into the game.