The GTX 770 is a 200 watt part.
If you go with an i7 figure that's a 100 watts.
add 100 watts for you board ram and drives.
And your at a max draw of 400 watts. Get a 500 or 600 to make sure you have a buffer and your good to go.
Just looked at your PC parts picker list, and that computer will use like 100 watts of power doing little thing like using the internet. It will draw around 300 while gaming, and if your into benchmarks or folding at home then you will see it hit its max draw of around 400watts.