your system is almost more than powerful .
You can go for 7 or 8.1 if you like . they are stable so far if we compare to 10.
i donot think you want your photoshop , crome other apps to crash under 10 .
or you can stay with your vista until windows 10 is made stable by MS people .
For ui in case of 8.1 or 10 you have to tweak a lot.
i cannot say you to buy or install 7 because it has more 3years of life left where 8.1 has more 6 years.
Its depends on you what you need. Try to find the os which will suit you . Thats all
Best Of Luck
Happy New year .
I personally on XP so i use it . You can stay with vista so far no problem.