CompUSA is one of the better places in the city if you're in the market for a new PC, printer, or software. Because they focus more on computers than electronics, they've got more stock, more brands, and their sales people are a bit more knowledgeable than at some of the electronic stores.
They also have a plethora of computer papers, labels, and cleaners.
They've also got a limited supply of MacIntosh periphinalia, if you can't make it to either of the Apple stores.
There's some camera equipment, too, but I'd stick with the computers if you come here.