Thanks for the answers, guys. I guess I was just spoiled by switching from XP to 7, when the system carried over all of my preferences and made D:\apps my default install path again without even asking. I'm discovering there are quite a few tweaks that the "upgrade to windows 7" feature carried over that are impossible to mimic using a clean install of windows 7. Oh well, I'm just being crotchety that I had to change the way I do things after 13 years of XP.
I know MOST programs let you choose where to install, but there are plenty that don't. Chrome and Adobe Reader both go to your default path automatically, for instance. I can't name the others off the top of my head, but there are a few that insist on being installed in the default path.