Your design would have become obsolute in about 3 months. Which is why everyone is saying you should buy a Dual Core. Because every PC manufacture is switching to a complete Dual Core line up. TO put it into perspective, AMD is releasing SIX new dual core processors, and only TWO new single core processors. Not to mention, Intel is goign to make the switch to complete Dual Core and Quad Core processors by the end of this year.
I believe the Pentium 4 is going to be replaced by the Conroe, and the Pentium D to be replaced by the Kentsfield. My advice is rather simple: If you're goign to build a computer, don't do it now.
Reason for this is also simple, if you purcahse a single core gaming system, your PC will become obsolute relativly overnight. Why spend $1500 on a machien that is flawed right form the concept? Just doesn't make sense.
Buy for the future Logan. Get a Dual Core processor, and buy a video card that will boast technoligies for years to come. To do this, buy either an X2 series dual core from AMD, or a Pentium D 9xx processor from Intel. Or wait even longer, get a Conroe or an X2 5000+. In addition to this, you should purchase at least a 7900GT, or an X1900XT or XTX. Yes, it's expensive, but, in the long run you won't have to upgrade liek everyone else will here in the next 6 months.
Plus, you MUST buy DDR2 memory. Every single motherboard manufacturer is switching to DDR2 as the standardized type of memory. Currently, only Intel provides DDR2 memory, which is why I suggested Intel to you. However, on June 6th of this year, AMD is launching their much anticipated Socket AM2, which also will be using DDR2 memory. So, why buy a computer that uses old and outdated memory? Save yourself money, go with a DDR2 system.
But hey, these are only suggestions based off of extensive research and countless hours spent reading through reviews and forums, but hey, what do I know?