Twenty bucks for a terminal emulator when there's already a perfectly serviceable one on your Mac? Secret Geometry's "Cathode" makes a good case for itself. It can look like nearly any terminal on any old flickering CRT monitor.
OSX-only Cathode is chocked full of class. Not only can you tailor each and every mode to your nostalgia gland's content, but even the try-before-you-buy mode is slick: instead of locking you out after so many minutes, Cathode instead degrades the quality of the terminal, making it flicker and waver even more than by default.
There are certainly a few bad memories unlocked by Cathode. Turn up the baud rate on the simulated modem connection and then list a big directory. You'll be overwhelmed by a gorgeous but totally unreadable torrent of phosphors.
The only thing I can think of that would make Cathode even better would be a mode in which it uses your Mac's built-in iSight to get an image of the room, then uses that to map the faked reflection in the screen.