2. I have a feeling when next gen hits and games start using more than 4 cores, we'll actually begin to see some advantage to hyperthreading. Seeing how I tend to run hardware into the ground, I'd want a CPU heavy build. GPU wise, yes, 780 is better than 770, but down the road, I can see high end gpus being bottlenecked more by the i5, if my calculations are correct.
Right now, the i5 and i7 perform about the same. However, this is mainly because games generally dont use many threads, and will not benefit from hyperthreading. This may change in a couple years.