Most of the magazine experts recommend using firewire (IEE-1394) to transfer from camera to PC. I've used USB2 and firewire and there is a distinct advantage in using the latter in terms of being able to ensure that you manage to get all the data off camera and into the PC with no drop out.
USB2 tended to give me a few hesitant moments during capture although I'm sure that there are many people who have dedicated PCs with no other "non-video" applications on them that would be quite happy with USB2.
I've got a few other things on this PC that run on start-up and it's a pain trying to shut down all the non-essential applications before dumping video onto it.
I've just found a piece of stand-alone hardware that might do the trick. Plextor ConvertX PX-M402U
www.plextor.be. UK price seems to be about UKP135 including tax.
There are bound to be others out there but that one was featured in the Nov 2004 PCW page 67 if that helps.
ST