Around 68-70 degrees, with a heat lamp (actually a ceramic heat emitter) in the corner of the whelping box for the first few days, depending on time of year. I also like to put a top over part of my box (it's a Jonart box) which holds in the body heat and lets the mom feel like she's in a den.
I love my snuggle safe, thats what I use in my box and its great for a trip to the vet. My room is warm at 70 degrees and if I keep it any warmer the pups fuss ALOT! I have only had two litters, so this is a novice talking, but so far its worked for me
For the first few days, I keep the room temperature at 70. I use a ceramic heating lamp (check the reptile section at the pet store.) The lamp goes over one corner of the box. I watch the puppies - if they pile up and are quiet, all is well. (When they are piled up, Mom is less likely to step or lay on one.) Once they start to spread out, I raise the heat lamp higher off the whelping box. If they start crying, I put wet towels or frozen water bottles in. I find that the pups don't need the higher room temperature or the heat lamp by the end of the first week. Always go by the behavior of the pups.