You're going to have a hard time getting someone to recommend a pre-built for you on this forum. Most of us, including me, are going to comment on this thread until we can get you to just make one and save yourself money/get much better parts.
Now before you go all "I ca't build one because I don't know jack about computers" on me, take 40 minutes of time and become a pro at building them. http://www.youtube.com/watch?v=d_56kyib-Ls
Its really just an expensive Lego set.