Actually not all of them work. most do but some dont. for a reference use this compatibility chart. http://xboxdrives.x-pec.com/?p=list
the only problem with that chart is it hasn't been updated in a long time I really want to get the "Western Digital Caviar SE WD3200AAJB 320GB 7200 RPM 8MB Cache IDE Ultra ATA100" (anyone know if it's compatible?) found the specs if thats any help http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=1540&p_created=1180116721