Good PC Setup

I am looking to eventually build a home cockpit, and want to have a dedicated PC for this purpose. I have been using MS Flight Simulator for quite awhile now, but, not really in a super serious way. I have been doing alot of flying, but, using the auto pilot alot.

I am going to be starting with LCD monitors for my cockpit, and maybe eventually building steam gagues for some of the gagues, and such.

I don't want to spend many hundreds of $$ to start out with, but, I do want FS9 to run well, and I do have FSX, which would probably be nice.

I am very good at putting together a computer, so I have no problem with buying parts, and have an excellent PC store nearby, or, would I be better off buying a pre-built PC?

I know I need a powerful graphics card, but, how powerful should I start out with? I looked at the sticky at the beginning of this thread, but, it shows so many cards, and I have no idea which is going best suit my purpose and pocket book. Plus, it appears that the graphics card might be closely related to which PC the card is going to be installed into.

My wife bought me a set of CH Products Yoke and Pedals a couple of years ago for Christmas, and then, a Sim Chair and Desk last year. So, I need to get at the business of getting this stuff put to good use!

Thanks in advance.