Just a word of warning, one you go retina you can never go back..

that about sums up my recommendation.

16GB is great, but from what you commented on as your needs you wouldn't have any problem with 8GB as it is. If you want to protect yourself for being able to do VM's, lots of photo or video editing in the future, or just like to have 50+ tabs open in a couple browsers at once then 16GB is going to make like a lot faster. But, for 200$. just for protection I'd probably put that $$ to something else.