This post has interesting timing. I had a laptop incident where
my 7 year old laptop finally cracked the case. Since this one of
my business machines it was time to replace it.
I did the scour the Ads for a decent machine. I found a really nice
deal at Best Buy

. The next day I went to purchase it (Monday)
and they were out. Well I wound up in Wal Mart and noticed an ad
for a Dell 1501 (Sempron 3600+, 1 Gig Ram, Ati Card, Broadcom
a/b/g and modem that works in linux) for $449.00. I looked at it
found it to be a steady brick and bought it.
This was purchased with the thoughts of using it more than the last
laptop. My investigation turns up that it is the same model Dell is
sold with Ubuntu on it.
This laptop was a dog with Vista. It now has Slackware on it with ACPI
setup (needed hand tweaking) The battery life is about 2 hours (still tweaking).
The biggest thing I look for in a laptop is the Keyboard, and solid construction.
Using a KB with the keys past the enter are annoying. The HDD speed at 5400
is fine. I have not upgraded the RAM since I do not get past about 500 Megs.
Good luck with what ever you get.
Bigpaws