Hi there. In my opinion, I don't think X58 is the way to go right now. You could get a Core i5 2500K on a P67 board with about the same performance for a better price. And also, the GTX 550 is probably not the best card for the money my recommendation would be either the Radeon HD 5770/6770 or the HD 6790.
Here are some of the parts I think you should use:
CPU: Intel Core i5 2500K ~ $220
MB: Asus P8P67-M Pro ~ $150
GPU: Radeon HD 6790 ~ $150
RAM: Corsair Vengeance 8Gb 2x4Gb ~ $90
If you do change some parts, remember to check if everything else is compatible.