I see that one of the tag is compatibility. For this allow me to suggest Kingston RAM as it is know for its compatibility and friendliness. I use the HyperX 1600MHz and it works great. If the build is mainly for games, then I see that faster RAM won't make much of a difference.
As for the CPU cooler, if you are not interested in serious overclocking, I personally suggest professional air cooling instead. Zalman has a good collection of those. But if the price was not an issue, then I believe liquid cooling would be a good choice.
Regarding the video card, the GTX 780 Ti you have, which is even better than the regular 780, is one of the best out there. I see that unless you want to play heavy video games on multi-monitor span mode, there is no need to go further.
Just my $0.02