I will suggest one but mine be abit off the beaten track.
Go on eBay and look for a Dell Mini 10V.
You should be able to get a N280 (1.66GHz) Atom version for just under US$375. There is a N270 version but no point going down that path.
Now here's where you need to spend abit more.
Get a new Seagate 7200RPM Hybrid Drive of 500GB size
Get a 2GB SODIMM RAM upgrade
and you need an external DVD drive for about US$40.
and a 8GB memory stick for about US$12?
Total will top out at about US$500
Here's where it gets fun.
You can DUAL boot the machine and run both Mac OS X 10.6.7 and Windows 7 on it.
I've used this machine for work and home and I enjoy it immensely. Never ever caught out.
I can run word processors, spreadsheets, iTunes and the GIMP for image processing.
You'll be the envy of so many.