If it's cores you want, why not go with a workstation motherboard and dual Xeons? Overclockability will be rather limited and price will go up if you want something latest and greatest, but us WCG crunchers have been building dual LGA1366 Xeon rigs for inexpensive prices.
I think it depends what your focus is on. If you want to lean towards gaming with the option for simulations, 5930k. If you want to lean towards simulations with the option for gaming, older dual Xeons. If you want both, maybe two builds? Build a cheap dual Xeon rig for simulations and a 4790k (or 4590k) gaming rig? I'unno.
If you're planning on gaming at 1440p, I'd suggest just going for a 290x or the GTX 980. Many will say wait for the 390x (or 980 Ti) and while I agree, it sounds like you want a card now and the only ones that'll do it well are ones packing horsepower. Bumping up to one of those cards will cost though and you may have to scale down one area to provide for this other.