I'm saying it now, because if it actually happens I want people to know I called it.
Last cylon = Tom Zarek. That has been my prediction since season 3, and I am holding to my guns, no matter how crazy and unlikely those guns are.
He's been a minor but kinda major player in almost every major event on the show. He is constantly getting himself into a position of power, but then hovering in the background so people don't notice him.
Plus - he has to be someone what's-her-number would recognize (When the cylon played by Xena sees the last cylon's face, doesn't she say "you"?). So it can't be some random crew member she wouldn't know. Zarek is a public figure. Yes, she was on the Galactica for a time and saw most of the crew, but she did little 10 minute interviews with almost everyone on board. I know they're computers, but can they really memorize and remember everyone's face that well? Would she have known enough about Gaeta, for example, to not only recognize him instantly, but to be surprised about it?
(Of course, now that I've said that, its going to be Gaeta just to spite me.)
Plus - He was the original Apollo from the first series, so making him the last cylon would be pretty funny in a meta context.
Also, I may end up going to a rodeo bar tonight and riding a mechanical bull instead of watching the premiere, so be advised that I won't be able to talk about the show until Saturday afternoon when I watch it online.