I have to say that everything does look good except for a few things.
1) RAM
You would better off just getting 2-1gb sticks, instead of having 4-512mb stick. That way if you do want add more memory, you will still have two slots available. I believe that you do have 4 slots available altogether.
2) Mouse
From the way your budget looks right now with all of those components, 40 more dollars can not hurt you. Upgrade to a Laser mouse. Its a lot of them out there and I have to say that the response on a laser mouse is far better than a regular mouse. I have the Logitech G7 and that thing is a breeze.