What is the best type of in-ground pool to install in the Northeast?

Concrete/Gunite with plaster finish. Durability and ability to stand up to the winters. Replacing vinyl liners is a pain, and the appearance isn't as nice as the plaster. You'll only get about 5/6 months a year out of the pool. Don't have a spa included in the build of the pool. Develop a plan so that the spa is integrated, but on its own system, so you can use it year round. Good luck.