How to Build a computer

Well I have been reaserching and also wondering what type of computer to build for sometime. Found this link from heaton research - pretty cool.

Now this raises a point why would I want another computer - a desktop that too?? I already have a Mac mini - that I am very happy about. I have a office laptop and I also great. But then why a windows desktop? So, here are the facts:

1. I want to do video and photo editing and so I need a fast machine.
2. Mac does suck sometimes - check this nice article by Russell
3. I do miss windows - most of the latest free apps come on windows and I can't try them on my mac or office laptop.
4. Also plethora of p2p software.

The configuration I am looking at:

AMD 64 bit, 256 MB video card, 160GB HDD and dual monitor support and ability to have upto 8GB Ram on the motherboard.

I am saving money for that! Can anyone convince me not to have that beast? I may end up pouring a $1k on that including the 19 inch LCD Monitor. Waiting desperately for Thanksgiving.