It all depends on the construction of the motherboard, in the event there is nothing you can do about it. In the event USB 1&2 are interchangeble and it does not matter. You are likely to obtain a new device as USB2 , 1 having now been superceded for some time. You may gae a nag saying this USB2 device would operate better on a USB 2 conputer. but in everyday useage terms you will see no diference.
It is possible to a. turn off the Nag -I am not sure how , others will come to the rescue on this I am sure. or purchase a USB2 PCI card But to my mind you would be chasing around for nothing very much, although a card is a better bet than a hub for extra ports. Go ahead and get the drive of your choice - it will work just fine.
I'm not sure what motherboard I have got (I'm a bit of a novice) My computer is Pentium 4 CPU 2.60Ghz 512 MB of RAM. If I'm not sure if I have got 1.1 or 2 am I better off buying an external disk drive using Firewire?
On one of my USB hubs it says 'SiS PCI to USB Enhanced Host Controller'. Is this USB 2 then? The others all say 'SiS 7001 PCI to USB Open Host Controller'. Can you have USB 1.1 and USB 2 on the same PC?