Given the demographics of the situation and the opportunity to appoint someone who will be the first {something} Chief Justice, I suspect that Bush will go with a woman and I'd think the contenders would really be either Edith Jones of the Fifth Circuit or Janice Rogers Brown. Frankly, since Edith Jones was rumored to be the runner-up to Souter and among the finalists for O'Connor's position this time, since it will be much easier to replace Rehnquist with a very conservative judge, and since Jones is both very conservative (more conservative, probably, than Brown) and female, she strikes me as a logical and likely choice.
There's little doubt that McConnell, Alito, Luttig, and Wilkinson are eminently qualified, though.