I've always wanted Jack to end up with Audrey, but it looks like they are slowly moving him toward Renee. I would be very surprised if he did anything with Sackhoff's character. Sackhoff seems to agree in the spoiler below, courtesy of TV Guide's Mega Buzz:
Is Katee Sackhoff going to hook up with Jack Bauer this season on 24? — Cliff
MICKEY: According to Sackhoff, her character, Dana Walsh, may not have ever hooked up. Dana is actually engaged to Cole Ortiz (Freddie Prinze Jr.), and Sackhoff thinks they might be waiting until after the wedding to seal the deal. "I don't know if Dana is going to get it on in the 24 hours that she has," Sackhoff tells us. "I think that it might be a little more clean than that."