Now the Key things you need to look at when buliding a computer is CPU, Mother Board, RAM, Video Card and Hard drive. Now with the Cpu there are many differnt options that you could pick from, if you are into computers and know alot about how to use them i would sugest an AMD 32 bit and than you OC it, if not i woudl go with a AMD 64 FX at a higher speed and be a step infront of everone once 64 bit goes full swing. When looking at a mother board i would get an Abit NF7-s for a 32 bit AMD or and Asus A7N8X Dlx, they are the best in my mind Nforce 2 mother boards. Now for the 64 bit the via chip set is good, at this point most of the boards out now are good boards for an FX just make sure you would get one that is compatable. RAM is extremly inportant to how a computer runs, i would go for at least 512MB to a max of 1GB of RAM, and right now the best company to get RAM from in my mind is Mushkin Menory, it is expensive but it overclocks extremely well and has great timeings and great proformance, i wish i would have gotten it insted of going for the cheaper Corsair at the time...... Now on to Video cards, i would go with a 9800 Pro from Ati, now make use you get the 256MB version and if you wanted go for the all in wonder, the XT isnt nesscary but is nice if you have the money. Now Hard Drives, what you want to look for is how fast the RPM is on the hard drive, get one that is at least 7200 RPM, ans look at the cache rateing on them make use you get a 8mb version not a 2mb it will make a huge differnce when gameing. I sugest a WD, thats becouse i had a great experience with mine but they are all about the same. Also if you plan to have this moster computer you need a case with good air flow and good cooling on the CPU and possably moding to the cooling that comes stock with the mother borad to acheive the best possable OC. If you have any more questions ill be glad to help you out in buliding a computer.
Chris Bakey