So, as a relatively new Mac convert, there are still some things that I miss from Windows. One of them was using SecureCRT. The thing I loved about SecureCRT (starting in version, 5.0, I think) was the tabbed sessions. I loved being able to have separate SSH sessions in different tabs and toggle between the tabs. During the course of a normal day, I need to connect to several different servers, and sometimes have two or three sessions open to the same server. This was managed nicely by SecureCRT.
But, thanks to a recommendation from Kyle and Dareus, I've started using iTerm on my Mac. iTerm supports tabbed sessions and has another feature that I love, not even offered by SecureCRT: window transparency. The greatest thing ever is to be able to see through your SSH window to other programs. Sometimes when I am working with information from an email that I have open, I can look right through my iTerm window at that email. Sweet.
I just started using iTerm today and so far I really like it. There were a couple of things that took some getting used to, but it is way better than the built-in Mac terminal that I had been using.