Hey ChillicooperS - You can try storing a cheap leather baseball glove under your seat to keep that new leather smell, it really works.
I thought about using bounce fabric softeners but I don't know If I want my cars smelling like a fresh load of laundry especially on my female customers, hmm just not sure how that will come across.
I currently use Mcguires odor buster it smells good does away with bad odors and last long enough to impression the customer, oh and leave them yearning for that experience again. Most people don't really care for most of the sents on the market anyway so I play it safe and only use deodorizers and not perfumes.