MacBook Air ram/processor help

I have posted on this site a couple of times in the last few weeks and have decided to go with the 11 inch macbook air with a 128gb hard drive. The hard drive space isn’t important because I have external storage, and I’ve been working with the same size hard drive so I am use to it. My only remaining questions are how much ram do you think I need and which processor do you think will better suite my needs? I game and most of my games require 2ghz processors, so the question is does turbo boost count toward the minimum requirements? So would it be a better idea to go with the i7 because it is faster or is the i5 ok for gaming? If neither work then it's ok because I have a xbox 360 too (I just prefer doing everything on my computer). Next is the ram I would like to keep this macbook for about 4 year and maybe more, so would it be a good idea to try to future proof it by upgrading to the 8gb of ram? Or will 4gb be enough to make it through a few years of os x updates? Besides light to moderate gaming I won’t be running any resource heavy apps. Any help is appreciated!

 

Was hoping to buy this by tomorrow (need it for work) so ANY help would be helpful!