Some useful applications

• Adium (Mac) - Great open source IM client that supports multiple networks.

• Chrome (Mac/Unix/Windows) - Great browser.

• iTerm (Mac) - nice terminal emulation app.

• Quicksilver (Mac) - Nifty launcher & a bit more.

• Omnifocus (Mac) - Task/List Management. How I stay sane. Based on David Allen's GTD.

• TextMate (Mac) - Great little editor.

• Putty (Windows) - Forget SecureCRT. Putty is ten times better and free. Better support for xterm-color, as well as ssh-agent like functionality (except they call it paegent), and a Windows <-> Unix scp utility.

• ssh-agent (unix) - If you still type in your password everytime you connect to a box, learn to use ssh keys & ssh-agent.

• x2vnc (unix/windows) - A very cool hack. At work, I have a Windows 2k and FreeBSD box sitting next to each other. Running VNC on the windows box, and x2vnc on BSD box, this allows me to seemlessly flip between systems, just by moving my mouse. (No more port switching!) It even let's my copy/paste between the two OS'es! Now that's just cooooool.
  Actually synergy is better.

• Tramp (unix/windows)- An emacs module for editing files on remote machines. Instead of ssh'ing in & running emacs on the remote system (which subjects to you lag & sudden loss of connections), run emacs locally & have it transparently move the remote file back and forth when you save. Like Ange FTP, but it supports multiple protocals (including SSH) and multiple-hops.