yeah i've been having the same issue on a toshiba satellite m35x laptop. when i bought it i upgraded from winxp home to pro. later i realized that of the 3 usb2 ports on the laptop (one on the side and 2 on the back) the side usb port would either not recognize my ipod mini or would say high speed usb device plugged into non highspeed usb port. I tested the port with my ipod 20gig and a usb2 wireless adapter. all had similar problems.
i exchanged the laptop at the store only to find the new laptop had the same problems except it was one the of the back ports. i tried winxp home and pro, same problem with both.
i had the replacement sent in for repairs at toshiba but they only restored the original hd settings and probably didnt test the device. i had the replacement sent again for repairs this time they replaced the motherboard. all ports worked the first time but soon all of the ports were acting up randomly. sometimes the ipod wouldnt be recognized or the connection would be made then dropped, made then dropped, made then dropped an indeterminate number of times and sometimes it would recognize the ipod but only at usb1 speed. i had the motherboard replaced again after convincing the tech that the problem still existed (it randomly worked for all of 10 min while trying to explain my problem to a toshiba tech)
i had similar problems connecting my ipod 20gig to my friend's shuttle xpc p4. the connection would be limited to usb1 even though it was an usb 2 port. luckily enough my amd 64 shuttle xpc has had no such problems.
my original guess was that toshiba's mobos are faulty, then i thought it was the ipod usb2 cord (i tested 2 different ones with no luck), now i'm begining to think its a winxp problem. but the random nature of the problem is very frustrating. i've tried both software (reinstalling winxp, itunes/ipod software, uninstalling/reinstalling usb2 drivers) and hardware fixes (cord change and mobo change).