Nice build man! I think you made a great choice in upgrading to the i7 rather than the 775. It will be able to handle any graphics cards you can afford in the near future, you'll have the 1366 socket for upgrading to future 6/8/12? core processors that will come out, etc.
So you could have built a system that would run better TODAY on the 775 platform, but I would have much rather done what you did - built up a system with some very strong components that you won't have to upgrade for a long time, and weak components that are easily upgraded in the future without a problem, and without losing much money on the upgrade, rather than just getting some medium all-around parts.
Have fun with the new build.
Oh, and don't let anyone else build it for you, especially for $150 CDN. That's... terrible. You need to learn to build a computer someday, so you may as well start now. Take your old rig completely apart and reassemble it before touching the new stuff if you're that nervous about it.