Of course 2015 MBP is the model I want. I just hope they keep selling it on 2017, because I plan to purchase it with the Back to School deal.
I get more battery, several ports I actually use (USB, Thunderbolt -mini DP-, the great MagSafe...), and one of the best keyboards ever made.
My only hope is they to keep manufacturing it for several years. That way, I will have plenty of years of technical support before it become obsolete. You know, changing its battery a couple of times in 8-10 years, WiFi module if broken, etc...