As far as I know the parts are compatible with each other, but I'd like confirmation. Also I'm not too sure if the PSU and cooling is sufficient, so any advice on that is welcome. And of course if you have any advice on any other part I'm very interested in what you have to say!
The cooling is sufficient but the psu is not...I reccomend al least a 600w psu (probably 750w) because I doubt a 400w psu will be able to power an i7 and a gtx 660. Personally I prefer the amd fx8350 over the i7 as its cheaper and works just as well.
As after overclocking (you will need more psu from your current selection)you would get very good performance on games and i5 can hold them very neatly and investing the rest in gpu would boost your gaming experience.