I can't believe I neglected to mention this in Monday's post on SQL Server 2005 SP2..
Among the many features of SP2 is support for the Windows Vista security model. SP2 is the first release of SQL Server to offer this support. I've been running this configuration on my laptop (HP nc8430 w/2gB RAM) for awhile now, and it's been a wonderful development/sandbox platform.
My apologies for the omission..