I agree that the MK trilogy is the greatest series to ever be put on a compilation disc. The Windows version of MK1/MK2 that was released as a 2-pack are the best ports of those 2 games (the Saturn MK2, and the nearly identical Japanese-only Playstation MK2 were pretty damned close though), and it's probably a toss-up between the PSX and PC versions of MK3 for best port there. MK4 was best ported on the N64 if you ask me, but MK Gold for Dreamcast was a lot better.
A wierd thing about the collection though - Primal Rage was made by Atari, not Midway. I guess Midway picked it up somewhere down the road when Atari pretty much died.
This is going to be the 1st time I ever buy one of these arcade classics discs, and I can't stand the wait.