What's a good terminal manager for OS X?

Taken in mind that setting up a tunnel by your self is really easy, you may consider using iTerm2 as a replacement to Terminal.app.

iTerm2 features profiles, so you may connect to any SSH server instantly.

Advantages over Terminal.app:

http://www.iterm2.com/

If you still need to use a gui for tunneling, then you may use an app like:

SSHTunnel or SSH Tunnel Manager

For SSH you just open a local Terminal and type ssh host.

You set up the configuration for each host in ~/.ssh/config following the rules laid down in man ssh.

I guess I don't understand why anyone would need a graphical tool to set up SSH, a command-line program.

I like JellyfiSSH - I've just emailed the kiwi dude that writes it & asked for an option to open new connections in a new tab rather than opening a window for every single connection. Otherwise I like it. Mind you I paid my $4 or whatever it was just to try it.