I've got a new Lenovo Thinkpad Edge on the way (14" AMD-based model)
they retail for about your price range - the Edge series is the first
to start moving a bit away from the 'Thinkpad design' - they mixed in
a few consumer things - keys changed, the frame isn't totally there,
but its still a Thinkpad from the reviews I've read.

I'll buy almost anything from a company that makes business models -
HP/Compaq, Dell, Lenovo - I can get a repair manual and spare parts
from either my distributors, ebay, or direct.  Toshiba, Sony?  I can't
even get a repair manual.  (Ended up finding some for two Sonys to
replace HDs on a Russian site - took some finagling to find those - 27
screws to get to the HDs!)

So yeah, go cheap and expect to replace it, or pay a bit more for a
solid case design and have it last - Lenovo's got some deals on
Thinkpads almost all the time.  Heck, they even have a netbook model
in the Thinkpad series!

If you DO look at thinkpads - http://www.thinkwiki.org/wiki/ThinkWiki
is the Thinkpad-oriented wiki for most things there.  They don't have
my model up yet, but I'm not terribly concerned - its an AMD/ATI CPU,
Chipset, and GPU.  I'll get it working :-D