Everyone who has been using a Mac for some time is in love with Panic, a small company that has been making awesome Mac software for a long time. I'm no different. I love Panic, and have been using their things for ages. I used Audion before the behemouth called iTunes crushed their cuteness into extinction. I use Transmit as my preferred FTP program. If I still used newsgroups (which I stopped doing a couple of years ago), I'd be using Unison.
Their latest offering is Coda, an all-in-one web development product. On the surface, it's awesome. Under the surface...I'm not quite sure yet.