I love Fission, by Rogue Amoeba. That's right, I said it. Do not judge the love between a man and this piece of powerful, yet simple to use, audio editing software. Fission 1.5 has just been announced (which is the reason for this post) and it brings some new features to this already solid offering. New in 1.5 is copying and pasting audio in a single document, or across files, gain adjustment, and a host of other things (including the often overlooked, but always appreciated, bug fixes).
Fission 1.5 is available now for $32 and is a free update for all registered users.