James,
I have just gone through this process. I have read and educated myself about computers in the process. One thing to keep in mind is that many people will have their own opinions and ideas. I kept looking for the "right" setup, and there is not a 100% correct answer.
Here is what I went with. I don't know how quickly you are able to get your new setup, but Dell in running a great deal on their Vostro model. You can upgrade it with as much juice as you want. It also comes with a video card upgrade option to the Nvidia GeForce 8600gts card which is a top of the line card, and you can run 2 monitors through dvi connections.
The deal is $330 off through January 31st.
http://configure.us.dell.com/dellsto...=brpc4gk&s=bsd
Just an idea.