I guess I’m too late to repeat my opinion that $1200 is WAY too much to spend for a computer IF you’re on a budget and just getting started. Currently, I use a self-built computer with a Q9550 2.3 MhZ, with 6 GB RAM and 64-bit Windows 7, and I have yet to ever run into “horsepower” issues. SSD is of course nice, but IMO you basically bought a Bugati in order to drive to work and back in. Also, again, regarding the expenditure on treatment: I have not spent all that much on treatment, but I’ve gotten my sound going in pretty much where I want it. Coming out still needs some work. But what has gone “to tape” has just the right amount of reflection-free but not dead that I wanted.
6 large 48x31x4" corner mounted DIY bass traps: $300
a standing 70" tall DIY dual-baffle: $50
Auralex panels I bought years ago: $350 (bought on sale)