Mr. Tea - I would totally show up to work dressed like someone from Mass Effect. If only I could find that hot armor....
Anyway, I always play as a guy in any game I'm playing. I just can't get into a game if the person I'm controlling is female, it's too much of an imagination stretch for me to get into the game.
I have a friend though who plays as a female character in a lot of online games. The reason is because he says he's able to get a lot of free stuff from guys who's only interaction with the opposite sex is through a computer screen. Thing is, he also flirts with guys, hard. This could be construed as part of the plan, but he'll do it for not gain, and in games that there isn't any gain to be had. We can remember him doing this as far back as when we were playing Jedi Knight online. (No, you couldn't play as a female character in that game, but he would pretend he was female when chatting with people we played with.)
This always kind of bugged us because it is really deceitful towards those on the other end. Sure, you flirt online with someone and you reap what you sow, but taking advantage of that is kind of...dirty. Plus, we (myself and this person's other friends) have long suspected that he's gay, and wish he'd just come out already. But hey, we could be wrong.