I was only marginally impressed with bioshock, it was so amazing at first then really dropped the ball. If they can improve on that and give us a fully fleshed out game similar to the first hour or two of bioshock then I'm there. I remain skeptical regardless of who is directing.
edit: also not sure if anyone has actually gone back to play system shock 2 lately but It was my favorite PC game back in the day and I can barely stand it now.