ChronusHan

It's not a proper stability test and drivers from both manufacturers throttle the GPUs. Besides normal use will cause thermal paste to set, if you have thermal paste that requires it.

Correct.  That is very unlikely something got damaged. 
However I stress test every new piece of hardware. 
Use prime95 to test the cpu for 24 hours. 
Use whichever benchmark you like to stress your gpu.  I recommend against furmark unless you know exactly what you are doing. 
Use memtest86 to test your ram. 
But your fears about the static are not warranted.  Happy computing.

Modern electronics are pretty hardened to ESD, modern MoBos generally have some type of ESD protection, a built up system usully allows equalisation of charges etc etc
 
To be honest the only way you will know if you have damaged anything is to try it and see, no third party (without access)can tell you if you have damaged something, you are unlikely to have damaged anything but the only way to know for sure is to try it

Intel Extreme Tuning Utility, Unigine Heaven, along with some real games will give you a good idea if your system is okay at the moment.

Well, at the time the 780 was cheaper than the 290. So, when I went to build my college rig, I already had a 780, so imo it was worth the extra $100 to get another 780 rather than a 290 that way in three years when I graduate I'll have SLI 780s. 
 
I also don't like multi monitor gaming; and finally, my "ultimate" plan is to stick with 1080p unitl 4k can be driven by a single gpu, then upgrade to a 4k monitor and upgrade my SLI 780s to something that can drive 4k. 

Price to performance wise, usually. If you're looking for the single most powerful card, then the 780Ti is it. But 290x's are quite powerful especially for the price--the R9 290 is on par with a 780 (non ti and is $100 less), and at higher resolutions become a necessity since 3gb of VRAM really isn't enough for multi 1440p monitors (surround gaming).