Oops, as you've already gleaned, Monkey, I was wrong about "archive and install" as it's been cut from this version.
The only persistent problem I'm having with 10.6 is I can't sync preferences with MobileMe. Not a big deal, really. On the plus side, upgrading did kill the annoying glitch where iTunes was asking for permission to make a network connection every time it was reopened. So that's a win!