I'm curious to hear any experiences on this too.
I'm running a VPS 3 from 1and1 (Windows Server 2003). I've got SQLExpress and MySql running on it and about 5-6 sites including joeaudette.com, demo.mojoportal.com, storedemo.mojoportal.com, and some demos for my clients. The VPS has a 500mb ram minimum and 50gb disk. It comes with only 1 fixed ip address. Seems to work pretty well so far, though I wish I could get more ram.
Joe