SCPlugin: Working SVN support in finder, or Tortoise SVN for the Mac if you like. This hasn't worked for ages, but finally got an update (credit limi on #plone): http://scplugin.tigris.org/
Inquisitor: to quote "Inquisitor... it's like Spotlight for the web. Start typing and websites pop up immediately, along with ideas to refine your search." http://www.inquisitorx.com/safari/.
Iterm: an ok replacement for terminal that has a few nice features, about 50/50 on if I should keep it at the moment: http://iterm.sourceforge.net/.