If you paid for Windows Live OneCare, in my opinion the top security software on the market for your buck, you had to make a tough decision when looking at all those sweet Vista betas.
See, OneCare didn't run on Vista, so you had to choose one or the other.
Fret no more! OneCare 1.5 was released today, and it supports all versions of Vista from RC1 and on. It is beta software (and I'm still trying to figure out what the hell perpetual beta users are supposed to do), and it looks solid (Paul Thurrott has screenshots). You can start installing it just by running this file.