All of the suggestions are going to give you a really fast PC for the money.
Once you have chosen the spec of the machine and priced up the parts you should ask your local PC shop (that probably builds to spec) how much they charge to assemble the rig. A warranty goes a long way when you have shelled out $1500 on parts.
If you are not worried about a warranty then you probably have the experience to build it yourself. In which case, you would not be asking others to suggest the spec of your new pc.
Most PC enthusiasts have Intel/AMD preferences, ATI/Nvidia issues and different ideas about which components go together well to reduce bottlenecking, on FSB's or Ram etc.
If you read the latest reviews of products and choose the mid priced items you can guarantee they will be good for about a year maybe two. The top end items will be good for about three years depending on advances in each area.
If you still cannot decide which components to match together for your budget you may opt for a ready built system with a warranty. I have found the gaming rigs on the market currently are easily capable of running the most upto date titles. You can even buy overclocked towers with basic liquid cooling and decent GPU's under warranty. This was not the case 5 years ago for example.
Obviously building your own dream machine is why most people are members of this site and we all like to squeeze the most flops out of our rigs, but I have built a few, bought a few and upgraded all of them, so Even if you don't have a headache choosing the components now, on your initial build you will def get one when you have the upgrade issues a year down the line and the latest tech is not supported by your ATX board.
Take the plunge and build something, even if you are not sure about how it may be criticised by your peers. At the end of the day when you power it up and run your first game with the GPU whirring, overclocked and the fans or cooler rad contributing to global warming, its out of date.