Play.com have the cheapest name brand 2GB laptop memory that I can find in the UK. It works fine in my EEE PC 1000H and ihas made a noticeable mprovement running Vista Premium.
I find Vista Premium with 2GB quicker than XP with either 1GB or 2GB. 1GB was a bit too slow opening some apps in Vista but 2GB works great.
This is great for the EEE because it only has one Sodimm slot.