MacTerm

MacTerm (was MacTelnet) on Mac OS X is now a complete replacement for Terminal, allowing access to both local and remote applications.
Its many features include powerful terminals (with or without tabs), a very flexible preferences system, TEK vector graphics, dynamic search, notifications and keep-alive, macros, a floating command line window, special keypads, a session manager, and even a basic Python scripting interface. It's also free software under the GPL.