Make sure you get a powered USB hub, not one that takes its power just from the USB cable itself.
I had an oddball occurence the other day that underscored this for me. My ViewSonic 2130b monitor has an integrated four port USB2.0 hub. I have my wireless Logitech keyboard/mouse combo plugged into it, which is convenient.
I am guessing that it is a passive hub though, because I plugged my iPod into another of the ports when it needed to be recharged. Almost instantly, I lost the use of my keyboard/mouse! I am assuming that the iPod took all the "juice" available from the hub and everything else stopped working. I had to manually reset my Mac to get control back.
So, get a powered hub!