First run or two probably as someone who talks (or tries to) their way out of things or uses words to solve problems. I've always enjoyed playing silver tongued characters, though from there on I imagine they'll get more and more unstable to the point where I say screw it and pretending I'm Luigi Largo brutally stabbing anything that slightly annoys me.
When I'm done with my Hero goodie goodie runs I'd love to try and rp a Rotti Largo kind of character, greedy, cunning, short tempered, holds one hell of a grudge, and wants those who wronged him to suffer in every way possible and take everything and everyone they love away from them.
Also if possible I'd like to try and rp as an OC I've been working on in the ME universe well the personality at least but probably won't work out too well since I doubt I can make her crawl around in the vents.