Allow me to second Larry Ribstein's motion that the President nominate my dear friend and sometimes co-author Edith Jones as the obviously best appointment to replace Justice O'Connor. She is smart, thoughtful, experienced, principled, and of impeccable judgment and character. An extraordinary person and extraordinary judge. As Larry suggests, she is the obviously correct choice for the slot.
In addition, Ribstein notes another key element of Jones's background that distinguishes her from many other excellent candidates--her deep experience in business law issues, an area in which, as Larry notes, the current Court is "sadly lacking." Given the substantial portion of the Court's responsibilities on issues including bankruptcy, securities, antitrust, etc., the Court could certainly use some additional expertise on those issues.
If the President decides to appoint a woman and does not decide to name Edith Jones, I think the clear other choice is my friend Alice Batchelder of the Sixth Circuit. Batchelder, like Jones, is smart and deeply experienced, as well as sharing a particular expertise in business law. She also has great judgment and common sense. She began her judicial career as a Bankruptcy Judge, then was appointed by President Reagan to the federal District Court for the Northern District of Ohio, before being named to the Sixth Circuit by the first President Bush. Batchelder is smart, thoughtful, and charming, and would also make a superb choice to the Court. Given Batchelder's immense experience and sound judgment, she may be a somewhat easier confirmation than Judge Jones (although, as I previously noted, I think it is going to be a fight regardless, and the goal should not be to try to avoid a fight, but rather to get someone actually worth fighting for).
Finally, both Jones and Batchelder would bring to the Court something that currently is sorely lacking--a real-world, outside-the-beltway perspective. The insularity of the Court today is quite striking, especially after the long stability of the Court's membership, and they must be oblivious as to what is actually going on in the rest of the country and how they are perceived in real America (sorry Justice Breyer, I don't count Cambridge as "real America"). It has been decades since any of them lived outside the northeast corridor (at least Justice Thomas gets out in his RV during the summer). It might be useful to have someone around who can pop their balloons every once in awhile and give them a sense of the real world. Jones and Batchelder, both of whom are absolutely loaded with good common sense and grounding, would certainly meet this test. Others on the short list, such as McConnell, Bainbridge's choice, obviously fit this bill as well (although Michael's real-world credentials are somewhat attenuated by his professional career as an academic...).
If the President decides to appoint a woman, it seems obvious that Jones is head-and-shoulders above the pack, with Batchelder making an excellent choice as well. As far as I can see, there are no other candidates in the same league as these two (assuming the President doesn't want to pick another fight with Brown again so soon).
[In response to some emails, I wanted to make sure that readers recognized that my crack at academics in discussing Michael McConnell's suitability for the Court was a joke.]