I don't have a lot of humidity in my house and I don't believe the foundation moves around a lot. Thanks for putting my mind at ease.
Again with the quarter round, I removed all the pieces and the creaking stopped. I haven't installed them back on yet (except for the piece in the closet), but I'm pretty certain the angle I nailed them was the problem. The nails entered near the bottom of the base molding and probably entered the sub-floor in some cases. I think the improper installation of the quarter round caused noise related to the interface of the laminate floor and quarter round. I was able to remove the quarter round without damaging it, but I'll have twice as many holes to fill. Oh well, live and learn.