I would highly recommend the Antec 300 case. It is a full-size mid tower case, featuring 2 built in fans with room to add 3 more. With a low price of only 44$, it is the perfect match for any gamer. Also, your processor is perfect, but do not use a stock cooler. I would recommend the Cooler...
Pentium 4 530 prescott 3ghz
Intel D865GLC
4gb pny optima ddr 400mhz ram
his ati radeon 4670 1gb 128bit agp video card
thermaltake silent power 480w psu
blue ray burner asus sata to ide converter
500gb 7200rpm ide hdd western digital
antec one hundred case
I would have to say the gtx 550ti as I use it personally. Based on price, it is the best value. I paid 200$ at best buy, but at new egg you could get one for 120$. The difference between the 560ti and 550ti is not very notice-able. I can play mw2 on the highest settings possible with the 550ti...