I'm not a huge Dell fan, but we've been looking to buy two laptops with WinXP and finally bit when we found the following deal
here from Dell for $649 w/ shipping:
Dell Vostro 1500 15.4" laptop/ 1.4GHz Core 2 Duo/ 2GB Ram
120 GB HD/ NVIDIA GeForce 8400M GS Graphics Card
8X DVD Burner/ 9 cell battery/ Intel PRO Wireless 3945 802.11a/g wi-fi card
Win XP home
For $215 more ($864 total) we upped the CPU to the 2.0GHz/2MB L2cache/800Mhz FSB (T7250) CPU, added Bluetooth and a 1440 x 900 display.
$338 more gets you a three year onsite warranty w/ drop/spill/surge protection and a $150 Dell store credit - this might be worth considering with many student (and mentor) handlers. This is pretty cheap compared to other abuse insurance offered, so perhaps Dell feels these will hold up ( or maybe they're just cheap to repair/replace)
The Vostro is fairly heavy, but from what I hear is built somewhat studier than Dell's earlier Inspiron offerings with a magnesium frame and sealed keyboard, and can be ordered minus the usual shovelware (pre-installed unwanted programs).