http://www.techbargains.com/ is pretty much my source for good tech sales. It's similar to the previously mentioned xpbargains, but the site appears better formatted to my eyes.
BTW: those limited time only Dell cupons? They repeat every 2 - 3 weeks, don't get overly excited. The same cupon will pop up again in less than a month. That said, my wife and I waited until one we wanted came back around and took $750 off her laptop.
I'll throw in on
http://www.newegg.com/
They rock. There's nothing more to be said if you need PC stuff.
http://www.tigerdirect.com/ is good for the same stuff as newegg, but Tiger's a little bit shadier. Your odds of buying crappy goods here are better. Then again, if you're a beliver in "if it sounds to good to be true, it is" then you'll be fine. I got a remanufactured printer for a good price, had no problems with my order, and the printer rocks.
http://www.thinkgeek.com/index.shtml for geek stuff. That's self explanitory.
http://www.retrobox.com/rbwww/home/ good site for me. This is a Columbus OH business (well, until they were recently purchased) that sells off-lease PC equipment. They are honest in product description and have good service. If you want a couple year old laptop for a good price, this'd be the place to look. Or, you've always wanted an HP 8100n at home, this is the place to get one. The stock changes pretty often. Just read the descriptions and you'll have a great time.
http://www.popsoda.com/index.html great place to buy unique soda pops.