it depends on how much music you're talking about.
let's say you have 20 GB of music.
to sync your ipod with USB 1.1, it will take almost 4 hours at that speed (12 Mb/s)
USB 2.0 can effectively get about 320 Mb/s, so it most likely will take less than 10 minutes to transfer 20 GB. Realistically speaking, it will probably take closer to 15 minutes.
So, figure about 40 minutes overall, give or take, to use the USB 2.0 ports on your wife's PC. MUCH better.
But, monster's correct in that you may have syncing issues with using a different PC. Although I haven't tried it, I think they improved their multiple PC syncing stuff in iTunes 7, so I'd at least give it a shot.
theoretically, it SHOULD take 4 hours, but realistically, it doesn't work like that in my experience. it seems to take its sweet time doing things like "analyzing song volume" and "checking for gapless playback" and "looking for album art".
i may set it up around 7 tomorrow night, and see if everything is done by the time i go to work on wednesday
ideally, i'd add the USB HD to my wife's USB 2.0 port, set it up as a mapped drive on my PC, drag and drop the entire mapped drive onto iTunes "library" - but it would probably take like 10 hours to add it to my library, so that would kill it.
FWIW, you can't drag and drop sirectly onto your ipod from a USB drive, unless you drop it into your library first. DRM at it's finest, people.
oh, right. i was really describing how it would work if you were to just attach the hard drive to her computer and use that to sync.
syncing itunes with a removable hard drive isn't really the best way to do it, unfortunately. itunes is very fragile when it comes to tracking the physical files.
and letting itunes analyze all the songs for gapless playback and song volume is going to take FOREVER on a usb drive. that's just torture. unless you've already done it somewhere. if it's completed on your laptop, just sync it with usb 1.1 on there and let it go overnight like you said.