I can't believe it has been a year since we started building our pool. I'm not sure that I would change anything, so I have some general thoughts:
Salt generator is definitely the way to go. We have an insanely low chemical bill as compared to our above ground. About all we add is salt and muriatic acid.
Pool controls - we had a wireless control system installed. If you want electronic controls, wireless is actually cheaper to install for a new build. Ours controls lights, heat, jets, pump, and cleaner. The only thing it doesn't turn on is the slide.
We started out wanting a beach entry and modified that to a very shallow shelf that you could put a chaise on, or can be used by little kids as a splash zone.
Budget for some mosaics. You can't add them later, so do it right the first time
We have a 3M finish that is smooth smooth smooth. No tearing up feet or bathing suits. It is smoother than the finish in my neighbor's 10 year old pool.
We went with pavers for decking. If one breaks, we can replace it. They save us a bit on taxes because they drain. Plus it just looks a lot nicer. Get more decking than you think you need.
If you are having a concrete/gunnite pool, your design options are endless. We made some changes once the builder sprayed the outline. As long as I stayed within the linear feet I was contracted for, I was able to bump out the back wall, make the dip on the other side a little less. I also changed the entry steps at that point because it didn't look as good on the ground as it did on the paper.
We had a couple extra pipes stubbed under the pavers in case we decide to add any water features later. I wanted something but couldn't find anything that really excited me, so we left the option open.
Heh. I just thought of something I would change. I would get the automatic filler and overflow thing.
I'm glad we got a heater, but decided to try the new solar rings to see if it would save any money. I am happy to report that they are working pretty well. We need a few more - bought what it said to get for our size pool, but it isn't quite enough. The builder advised against solar heat because he has seen too many problems with it.