When processing dialogue for my clients, I almost always turn to Izotope's dialogue de-noiser in RX5 Advanced Audio Editor. But as I've mentioned, this is a pricey piece of software that retails for $1,199 USD.
First off, why do I use RX for de-noising when I already have a pretty solid de-noiser in Adobe Audition? Two main reasons: the RX de-noiser is super simple to use with two main settings and because I end up with better results in most cases with RX - fewer artifacts and strange, harsh, robotic sounding dialogue.
Interestingly, Izotope has now released the RX de-noiser along with de-clip, de-hum, and de-click as a pack of plugins for $99 USD. That's a pretty good deal if you need to use this type of processing on a regular basis. You can find more details over at Izotope's site (I have no affiliation with Izotope, I'm just a happy customer).