Finally time to upgrade. Things broke and now I have an excuse

So here's what I've got. This is my current build minus cpu and motherboard: http://pcpartpicker.com/p/9jM6Vn

I need a new cpu and motherboard combo due to a 'miss hap' while tinkering... Long story short, the cpu is slowly dying and needing to be down-clocked to stay stable. Now this comes at a kind of ok time as I have some money to upgrade so I'm looking at going either with a Xeon 1231-v3 or a 4790k. I would wait for broadwell / skylake but I don't have the time or cash to deal out for a non-discounted motherboard with all the features I want. I need lots of usb. 6-8 on the back panel is needed and I need at least 2 to be usb 2.0 for compatibility reasons. I will probably be buying a 780 ti or 980 off ebay soonish so that will be replacing the 770 4gb in there. So I'm looking for tried and tested motherboard combinations. To save some cash I was wondering about something like a Z87 Asus Hero and a 4790k when broadwell comes out and there are some sales on that chip. Otherwise I'd be opting for the same motherboard and a Xeon 1231-v3.

But, does anyone know if I can transfer that windows key? If I can, the $350-ish I have to spend is more like $400. What would you all recommend? I would rather keep the DDR3 so no X99. I don't want to deal with quadcore's without hyperthreading so no 4690k. At the price of the 4690k I'm going for the 1231-v3 every day.