I think so too. or, at least I hope it doesn't cost an arm and a leg. In my limited research, it looks like the ideal speed would be about3.6Mhz, and 4GB+ of RAM.
of course, I don't know jack when it comes to that level of computer detail.
I just want something that is dedicated to FSX, that won't lock up, or be jerky etc.
I'm also going to get it set up using the plans on here possibly:
http://www.rogerdodger.net/diyflightsims.html