Well first get rid of the notion that Scalia and Rehnquist are Strict Constructionist. Both are slaves to the doctrine of stare decisis. Thomas, OTOH, is quite willing to overrule a bad decision, which is why he should be elevated to Chief Justice (I'm not saying he is perfect because he is waaaaay to willing to swallow hook, line and sinker any testimony from law enforcement, school officials and other government types).
Garza would probably overrule Roe, which, for all the exploding heads out there, does NOT mean the end of abortion. It merely means that each state can decide how they wish to regulate the matter. Garza would be excellent on 2nd amendment issues and I believe he would be good on 9th and 10th amendment issues also.
Go here for rulings that are in jeopardy with an O'Connor retirement:
http://www.sctnomination.com/blog/archives/2005/07/which_important_1.html
Go here for a review of several potential nominees and several articles on why Gonzalez should never be nominated:
http://www.sctnomination.com/blog/