Likely to be echoed many times later: Build it yourself or have it custom built for you. I have some extensive experience with computers, and can say that if your system is designed around what you want to do (not what's the latest and greatest or coolest), yu will always have better results than if you pick it up off the shelf or tinker with it a hell of a lot.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)