QMidi is the ultimate MIDI/Karaoke player for the Macintosh. It can play all kinds of MIDI files, no matter where they came from, in any order, using either the QuickTime musical instruments, Opcode OMS, MOTU FreeMIDI system, or serial port interface. QMidi also incorporates a MIDI mixer + GS effects.
BRIAN KENDIG This application is the ONLY way I've been able to find to play a MIDI file from a Mac to an external synth, ever since QuickTime stopped supporting this. (Version 1.7.2)
RAY This software is really great and better than anything on the PC (closest on PC is Van Bosco which is good too - but Qmidi is easier to use, and has the 'mirror' feature which is neat).
The old version 1.5 was sometimes unstable, but I've had no problems at all with 1.6
All that's needed to make it perfect is the ability to edit /add lyrics from Qmidi - that might be asking for too much, but if it could it would be all you need!! (Version 1.6.1)
TIM I've been using this program for 4 years and it's just wonderful - stable, simple and effective. One thought I want to add. If only the developers of this could expand it into a mid-kar CREATION program. This is sadly lacking in the Mac world as far as I know....thus I do my creation work on PC and move it to Mac - it works but it's a pain. (Version 1.6.1)