How and Where to get a new computer built

[jacattac]

I've been looking into buying a new computer for a while now and feel that for the money, getting a new Dell may not be the most economical route. I hear people saying that they build new computers all the time and I have seen guys on ebay that build computers for pretty cheap, but I have no clue if they are actually a good deal. All that I want is to replace my 1998 machine with something that can run multiple programs (lots of ram) 2 monitors (dual dvi) and last me another 5+ years. If anyone can send me a link or lead me in the right direction, I would greatly appreciate it.