:wq is a natural extension of :w, and half the time I haven't even decided to quit Vim until I've already typed the :w.

It's an extra thing to remember. When I'm coding I usually just do :w, so when I'm editing config files I do :wq because it's the same thing (write the file) plus a new action (quit) in my head, instead of a totally different action (save and quit)

There's also ZZ which I find easiest of all.