But I have never, ever, ever, thought "dammit! If only I could plug more USB memory sticks into this infernal machine!"
In fact, the only time I'm ever using a USB stick is to sneaknet some files to someone else (because in the year 2011 we have yet to figure out quick, painless filesharing with people you're physically near by. though Dropbox is starting to get ubiquitous enough...), and that hardly requires more than one USB port.