I'm assuming quad-core minimum, 8GB ram best.
Yes hard to say - no one really knows as yet, but Stardock do have a reputation for getting the best out of hardware by design, not forcing users to buy a sledgehammer card to overcome shortfalls in programming.
Quad/8Gb I reckon will be a given as a "standard" hardware bundle, would be crazy to buy less - anyway its getting harder (as such) to find duals -usually old stock or throw away bargins now, duals are not worth it in the long run if you are buying now. Do remember they will be releasing Autumn 2014 at the very earliest, more likely Spring 2015 as they have always said in their roadmaps. They will design for the hardware that's commonplace then, and for the likely hardware 2015 to circa 2020. Choose hardware that struggles now, or is a minimalist solution now, and you'll be disappointed I suspect. Do remember they have flagged they will be 64bit only - make sure you wind up the new PC as 64 bit - to all intents and purposes 32 bit is dead now. 32bit will be used for many years for sure, but increasingly its going to be a 64 bit only world. Most PCs are 64 bit capable now - unless individuals have one many years old.
Another way to approach this is get "throwaway" old second hand GPU card(s) that will keep you going for 18 months when you get the new PC, they will be dirt cheap. Then invest in the correct card 2015. Meanwhile a Quad/8Gb is dead safe as a base platform. AMD CPUs will be fine of course, just don't expect to get the same level of flexibility and power that you can get from Intel.
The difference between Intel and AMD is not that obvious to many at the moment - as such - for the average mainstream casual gamer, but the days of genuine full solution (not fudged) multi-core gaming are fast approaching, and there is little doubt the Intel multi core solutions will stand out for speed etc by far in such cases. However, its still going to be true that AMD will offer a good solution for the average gamer, even then - not everyone wants to compete to be the latest and greatest in speed. Just don't expect AMD CPUs to break performance records with genuine full solution multi-core gaming that will be with us 2015, they are not built to do so. They are well designed economical alternates for those that don't need or want cutting edge full solutions, but AMD will never take on the Intel chips long term, both are made for different markets.
The old adage, pays your money takes your choice.....