also you should consider what you're going to use it for, particularly for things that need high speed.
I did some speed testing awhile ago with USB and hard drives, and collected a frighteningly wide variety of readings. Low end was 6mb/sec. High end was 35.
Chaining hubs is all kinds of bad news. That, and PowerPCs for some reason are dog slow with USB hard drives. (yes, with 'high speed' usb, and installing a USB card did NOT help matters one bit) So if you need more ports and want to keep your speed, (and have an intel), then install a 4 port card.
I bought several of
these - they're cheap, reliable, and fast.
