iTerm (terminal for OS X)
Being used to Linux, I was not satisfied with OS X terminal. I do not know, something was wrong with the fonts (esp. when I had to edit Greek text), something was not right with the terminal emulation mode when I SSH-ed to linux machines. Then I found iTerm which is GREAT!
I also liked the "Bookmarks" and "Profiles" features.
Highly recomended if you work at the command line on OS X.