Beautiful software. Seriously. Software made for the OS X tends to be good looking in general, but some stuff is just gorgeous.
AdiumX – Free multi-network instant messaging application.
NetNewsWire – RSS reader.
Acquisition – Mac p2p client.
Inquisitor – Instant search extension for Safari.
Path Finder 4 – An innovative file browser and manager.
Cyberduck – FTP for Mac OS X.