I have been running Ubuntu on Microsoft Virtual PC 2007 on my Dell laptop for a good while now. It and all my Google Docs for notes, FreshBooks for time-tracking and billing, and production-hosting through one of just a few VPS hosts, affords me the portability of development wherever I go. I haven't figured out how to fold up my 24" flat panel yet, so for the most part design work gets done at home base.

What works for you? Are you also on a Windows PC?