The early word is that Bush will nominate Michael Mukasey for Attorney General. You can read Jeralyn Merritt's post on his history of rulings, Steve Benen's post on how he's regarded by groups on the left and right, or look at his Wikipedia page. Unfortunately, much of the information out there now is of the strange hall-of-mirrors form where you want to like him because right-wing bloggers are disappointed with him because Chuck Schumer and Nan Aron like him.
Putting everything together, he looks like a staunch conservative, but one who will be independent enough to not let Bush get away with Gonzales-era politicization of the judicial system. In a best-case scenario, he might pull a Paul O'Neill and rebel if he gets fed up with Bush Administration malfeasance. And going into 2008, I want to be confident that the AG's office isn't going to be used for nefarious election-year partisan plots. Mukasey doesn't set off any obvious alarms there.