Sublime Text 2 (http://www.sublimetext.com/) and MacVim (http://code.google.com/p/macvim/) are my preferred text editors.

Sparrow (http://sparrowmailapp.com/) is my favorite email client.

I can't live without a window resizer on OS X. Use SizeUp (http://www.irradiatedsoftware.com/sizeup/) for easy window maximizing, half splits, and quadrant resizing.