The one I'm using to type this has been pretty good for me, if it's any help.
It's an Acer Aspire One D150 - There's a few different specs available, but mine is:
Intel Atom N280 Processor
1Gb RAM
160Gb HDD
Wi-Fi
Bluetooth
Builtin 3G MODEM
10 inch Screen
Builtin Webcam
And it's blue too!
It cost 799CHF, and I use it with a mobile broadband subscription from Orange. So I can browse the net anywhere, which is really handy for checking EF of course.
As for performance, it's really good - not super fast, but I installed Windows 7 and Office 2007 on mine (instead of Windows XP that it came with), and it runs just fine. I always have it connected to either Wi-Fi or 3G when it's on, and I get about 5-6 hours battery life. Which translates for me to about 2-3 days between charges.
Mine came from Interdiscount in Marktplatz Basel, and they had cheaper versions without the 3G, but also with smaller batteries.