Its very hard to empathize with someone who has a 17" aluminum macbook pro (expensive), a recent iMac, and a $400+ per month lease on a car (must be a damn good car too). Your problems are not so much financial as they are a lack of priorities.
I gotta be honest, hearing someone contemplating how they could buy a Mac Pro when they have the stuff you have is like hearing an investment banker wondering how can he afford a new Yacht when he has 5 vacation homes around the country. It's kind of a duh situation - get rid of some of your other crap and get the stuff you NEED (and I don't care WHAT you do for a living, NO ONE NEEDS three different Macs, they may be NICE to have or convenient to have, but they are definitely not NEEDS), then later focus on your wants.
But good luck to you! I am glad you got the system you wanted. Sounds like if you can get the work now to pay it off you will be home free. It sure as hell sounds like you are willing to work hard to get what you want, which is great. In the future I would recommend prioritizing between wants and needs better, then you will be unstoppable and you won't have to worry about getting what you NEED to get ahead.