Thanks for all the advice and commentary.
After copious online research, and a long chat with the guy doing the piercing, as well as a few of the people he had pierced in the past, I got them both done.
The procedure was surprisingly less painful than I had expected, and considerably quicker. I experienced more pain having the tribal band tattooed on my arm. On the whole, a pretty good experience all around.
So far the only down side is having to force myself to sleep on my back, as I prefer to lie on my stomach. They are healing nicely, so if that's the only down side than I can definately deal with it.
That being said, I think I'm all set as far as piercings go. Nipple rings I can cover with a shirt, others would present a problem with the more appearance minded folks in my profession.
As to the nipple sensitivity issue, I haven't noticed much of a change, diminished or increased. At this point I pass off the slight increase to the fact that I am still healing. We'll see in a month or so.
It's been a very educational experience all around. I've discovered more about body modification than I ever thought I would, and I picked up a few interesting facts about niobium alloys, should it ever come up in conversation.
On the whole, a great experience.