I'd say cpu is most important. I could run 8 on my 3770k (clocked to 4.5 ghz). maybe more but i haven't really tested it. So I'm assuming i7 4790k cpu (which is the one i'll get when i build my next rig) would be able to hold 10 pretty easy. After that everything falls in place pretty simple (ssd, 32gbs ram) as for a graphics card, might as well get a good one just in case you need ur rig to bot other games. As for a gpu with vm's, I'm still fixed on the idea that you won't need one with poe (since vm's don't use the card), some ppl say they do, but I'm going to try a botting rig next week and test my theory out and see first hand.
