I use Sony EZ Audio. works fairly well. dehisser, denioiser for ground loops or crowd ambience, varying degrees of success. Declicker and decrackler, again with varied success. Graphic eq, reverb, echo, compressor.
I like the program overall. If the problems aren't severe, it does a pretty nice job. more severe noises cause swimminess and mp3 sounding results. Very cheap though. like $50.