Lol they're probably sold by uber n00bs who dont realize that their crt is worth alot more. Anything that noobish amuses me, like commercials that say we'll install drivers and printers 24/7!
Also, I would definately go for the 4000+ CPU over the 3600+, because if you are unlucky with the chip, and get a bad overclcoker, then you are at least guaranteed a bit extra speed, for a small price increase.