It's always a LOT easier and cheaper to wire during the build process when you have access to the inner walls so now is the time to go all out and if you end up never using a jack, well no big deal.
Nick's question is valid, as too many speakers in a small room is probably overkill but as you have pointed out, new standards are changing the way we think about the placement of speakers.
My room is 12x23' and I prewired it for 7.1, although I have an extra center jack so there is one both above and below the screen. Also, I have multiple subwoofer jacks wired everywhere that you might consider them. Right now, I only have one sub but I have a desire for two subs to help smooth out some lulls in my room and I wanted to be able to place them where this works the best. Presence and other new speaker positions were not top of mind when I prewired but honestly, right now, I don't have a big desire for adding more speakers. Maybe in the future, if and when those new standards become more prevalent.
