srry for the slow response but its exams time and i barely have time to check GD .
regarding the rig it self, everything you chose is great, very strong and well balanced, but the PSU is a huge overkill, something like a 600-650W will suffice even if you overclock the hell of both the 2 7850 and the cpu.
as for the SSD ill jsut recommend either the expensive but very reliable intel 520 or my personal choice the crucial M4.
the UPS, im not good with that stuff (amps watts and shit like that) so i cant really say but i think that the more juice the better. you will need that thing to power a very powerfull rig and 3 monitors so you will need a strong battery, also the battery wears out and a strong battery is needed to hold it for quite a time.
so go for the 1500 model but check that the company isnt generic and its from a good brand because some UPS deliver bad elctricity (naughty even) and it can cause problem with the hardware. also check if it has a fluent trasition between pass thru mode to battery mode because unknown and generic UPS tend to give a small "brown out" when you have power cuts(when it takes time to the UPS to change into battery mode and it causes a crash and by that you are losing the sole porpuse of getting it).