Intended usage and budget would be a great help, but if you're just looking for a place to shop, I would recommend
Dell's Outlet. These are typically factory certified refurbished and/or scratch and dent systems. I picked up my old laptop as a scratch and dent (though I never saw the scratch or the dent) for about 60% retail. That system lasted almost seven years before the motherboard finally died.
I'd recommend looking through their
Coupon Page for even better deals.
-Wolf sends