My own view is this.
In terms of raw performance for gaming the following will help the most in order.
SSD - SSD and CPU order can swap around depending on game
You chose to reuse old hdd and only buy a small SSD which wont hold many games. Also reusing old GPU.
Have you diagnosed that your existing cpu is the bottleneck?
on amazon a 7600 is £210 whilst a 7600k is £229, based on that pricing the plain 7600 is a pretty bad buy, the 7600k has an extra 300mhz speed out of the box and is unlocked so can overclock it, you can get a 7600k probably to 4.5ghz turbo speed quite easily and even with the automated overclocking tools on motherboards. You saving under 10% of cost and losing probably 20%+ performance.
Similar with SSD, the price per gig for a 120 gig drive is much worse than price per gig for 250gig.
850 evo 120 gig £60, 850 evo 250 gig £90. With games been as large as 20+gig now days I would also say the 250gig ssd is a no brainer.
Like the above comment you definitely want to wait for amd ryzen to be released, even if you still buy intel, intel prices are very likely to drop as a reaction to the new competition.
Edited by Chrysalis (Mon 20-Feb-17 09:04:41)