If you have the $$ I'd suggest getting at least the 128GB. You will find with app like Facebook, instagram, Snapchat etc, just gain space over a while from usage.

and with the iPhone camera being so great, you'll want to take more photos and videos. Which will naturally take up space.

I've had 64GB for the last few years, and it was more than enough. I got the 7, there was no way i was going back to 32, so i went to 128. There is so much room for activities (Step Brothers). I was able to sync a bunch of tv shows and podcasts and things just because I dont have to worry about the space. 32GB would obviously fill up faster then 128GB and that would be the worst part, being stuck with a phone you constantly have to monitor space and worry/delete things.

On top of that, the 32GB versions apparently have a slower Flash memory, but what that means in the real world, you might not notice.

I just think, Plan for the worst. Traveling for days without signal, you want more stuff and 32gb will fill up fast and be a limit. 128, you've got a lot more freedom.