My dd uses the Nuk Silicone pacis as well. She would nurse to sleep and then, when I could tell she was just "sleep sucking" I would unlatch her and pop the paci in to make the transition to lay her down to sleep. I only give her one during the day if I know she's not hungry (i.e. just nursed) and she's fussing. And of course in the carseat, where for the first 3 months, she always seemed to be fussy. Babies just need to suck, even when they're not hungry, so if a paci helps to soothe them, I'm all for it.
(that last line was more for my MIL and BIL who are both rather anti-paci people and of the CIO school of thought)