I"ve killed a few between 500 and right at 600 (muleys) with the 115g NBT @ 3200fps. Hitting the shoulder usually resulted in a DRT, behind the shoulder they ran about 20-30 yards and piled over.
How far are you wanting to shoot deer??
I would say realistically, that 800 would be the max (for me anyways), and thats using a 115g VLD or 125g Wildcat ULD. The added BC would help retain energy, velocity, and cut on the wind drift as compared to the 115g NBT. I've never tried the 115g VLD's, but I"m about to load some up right now and shoot them in a couple days. Dont know if I"m going to use them on deer or not, time will tell.
If you run the ballistics, the 115g NBT @3200 has 1000 ft lbs at 625 yards, and still traveling 2000fps. The NBT will reliably expand down to about 1500-1600fps, so by that number, you are at about 900 yards for reliable expansion, however at 900 yards your down to about 625 ft lbs of energy. Thats a little less then I personally want on deer, I like to have about 800 ft lbs and that would get you to about 750 or so with the NBT.
With the 115g VLD @3200fps, it will give you 1000ft lbs at 725 yards and still traveling around 2000fps, so it gives you 100 yard advantage over the 115g NBT. You could probly push 900 with the Berger or Wildcat VLD's as they still have about 800 ft lbs, and traveling 1750fps.
I would say it depends on what you think is the need for your energy and velocity requirements.
Still I think 700 with the 115g NBT is about max, and 800 with the VLD's, but thats just me.