http://www.aces.edu/pubs/docs/A/ANR-1061/ANR-1061.pdf

I use tables like that to check the optimum soil temp for my starters and germination. I tend to split the difference and keep the soil around 75 degrees or so.

Chris - The Table you linked to is great for germination temps, but gardengolfer was asking about post germination temps. From everything I have read it can be considerably cooler once they have developed true leaves. Hotter is better, but they should do fine as low as 65 F.

As a first timer last year I had pretty much no extra heat (other than the fluorescent bulbs) for my pepper plants, even for germination. I was growing in a 60-65 degree room. The smaller Anaheim peppers were prolific, the Bells produced fruit, but not many, but I dont think it was due to how I started them.

On the other hand, I just bought one of those reflective "emergency blankets"($1.98) which is basically a big sheet of mylar, and have hung it as a curtain over my shelves. The temps shot up ten degrees, just holding in the heat from the bulbs.