I use Xemacs a lot and I was having trouble with C-w C-u and other common emacs key bindings. Turns out there is a setting in the Keyboard Systems Preferences Panel that adversely affects the passing of keys to Aqua applications. Changing the Keyboard Access mode to Function Keys instead of Control Keys really made a big improvement.

SSH and SCP (client and server) are built-in. This is what I use to get into my corporate network.

One thing that’s different under Mac OS X vs. and X11 environment is that your window manager isn’t the parent process of your terminals. So what? Well this makes it very difficult to run ssh-agent and have your keychain (of SSH identities) work the way you might be used to under X11.

I’ve been using SSH Keychain for a while now and really like it. Works with the OS X keychain and your identities.