1k -1.5k including OS, monitor?
On the lower end of that budget,
AMD Phenom II X6 1075 + Gigabyte GA-890GPA-UD3H - $471
Kingston ValueRAM 2GB DDR3 x2 = $58
Leadtek GTX460 1GB OC = $255
Samsung HD103SJ 1TB - $75
DVD Drive - $35
Any casing you fancy = ~$75?
Total - $969 w/o OS or monitor
Prices taken from Bell Systems pricelist dated 20/01/11
Why not Intel? The current LGA1156 sockets are nearing their
EOL, but the faults with the LGA1155 mainboards (specifically the
chipset) are keeping them in the market for quite a bit longer. If
you are able to stay off purchasing the PC until April or May, when
updated mainboards arrive, I should be able to recommend an
Intel-based PC.