You probably won't get much choice between Gi or no gi, depending on the school. Make sure your fitness is at a good level, as it's harder than it looks. Gi is cool because of the grips etc.
Yep, I agree - Silva didn't gas, he just got thoroughly broken. I still have no idea how Fitch managed to escape that RNC, though. Fights like that make me want to give BJJ a whirl. I noticed a school opened up near my way. Anyone had any experience? What's more fun: gi, no-gi?
BJJ schools can be expensive though. Make sure you don't get stuck in a McDojo, research the school and if possible, have a look around for other schools in your area to try and get a feel for what should be a fair price. Try and avoid anywhere that "guarantees a black belt" within a certain time.
Have a look around here http://www.martialartsplanet.com/forums/index.php and see of the school or the teacher has been mentioned and what their reputation is like. Also, most school will offer some sort of free beginners course before asking you to commit to any payment, so try and avoid anywhere that charges you upfront without you having even tried it.
Most of all, try it, and have fun.