gm98 :
I'm a new builder and was wondering if the AMD FX8350 (stock speed) would work well with the EVGA GeForce GTX 780 3GB Superclocked ACX? Here is my spec too... http://uk.pcpartpicker.com/user/gabriel98/saved/pvhKHx
Yes and no... it will be very game dependent.
Allot of newer games (e.g. Watchdogs, Battlefield 4 etc) use multiple cores well and the FX 8350 shines. Unfortunately allot of older or lighter games that only use a couple of threads (e.g. most MMO titles) will be held back on the 8350 as they can't use it properly. This is why the general consensus is it's best to game on Intel as you'll get more consistency.
The other thing to consider is AMD's Mantle can be a real benefit in supported games on their processors, so you might get more out of an R9 290 + FX 8350 than the 780 (although as it stands there's only Battlefield 4 out that uses it, many more mantle games are due out).
Having said all that, you're proposed rig would run almost anything well (depending on settings) it's just worth bearing in mind that in some titles the 780 might be held back a bit compared to a similar system using an i5.