Ignoring Cory, my gaming OS 9 Mac is actually a Power Mac 7300. It has a 800MHz Sonnet G4, a Rage Orion and a GB of RAM, plus two 7200rpm SCSI drives and a 24x CD-ROM. This plays great old games like Deus Ex, System Shock, Bugdom, DOOM, Unreal/Unreal Tournament, Voyager Elite Force, Dark Forces, Duke Nukem 3D, Pro Pinball, Oni, Carmageddon, Descent I/II, Quake I/II/III, Wing Commander III, Shogo MAD, you name it (yes, those all have Mac OS ports; there's a lot more where that came from). Stick in a USB card and use your favourite mouse, though I just use an ADB one. I ripped all the CDs to the hard disk and just mount them as images; only a few won't run that way.
I also stuck an OrangePC 620 in it with a 400MHz K6-III, which boots Windows 95/98 for specific titles. (For DOS games, I have an Am5x86 with ISA, which seems to run certain EGA titles better.) The only glitch here is that the OrangePC software does not like the G4 card unless I disable both the L2 and L3 caches; it does seem to be fine with G3 cards.
As a gaming card, I prefer Rage 128s to Radeons even though the Radeon is usually higher performance because they also have a lot of graphics glitches in some early 3D games that were never patched. Shogo MAD, for example, displays totally bogus polygons until you apply a Radeon fix, and Quake II never got repaired (so on my Radeon 9000 MDD I have to play it in software rendering or the graphics glitches become unmanageable). Obviously pure software-rendered games don't have a problem but there's not much rendering advantage then either.
I prefer to use my MDD for heavier OS 9 crunching tasks like Virtual PC or CodeWarrior. Relative to the MDD, the 7300 is smaller, more reliable and generally quieter, though the OrangePC card and Sonnet G4 have their own cooling fans (but nothing on the MDD wind tunnel howl). But you have to do some upgrading to get it to the point where it does well, and that will certainly cost more than an MDD, or even a DA G4 or Quicksilver.
I also stuck an OrangePC 620 in it with a 400MHz K6-III, which boots Windows 95/98 for specific titles. (For DOS games, I have an Am5x86 with ISA, which seems to run certain EGA titles better.) The only glitch here is that the OrangePC software does not like the G4 card unless I disable both the L2 and L3 caches; it does seem to be fine with G3 cards.
As a gaming card, I prefer Rage 128s to Radeons even though the Radeon is usually higher performance because they also have a lot of graphics glitches in some early 3D games that were never patched. Shogo MAD, for example, displays totally bogus polygons until you apply a Radeon fix, and Quake II never got repaired (so on my Radeon 9000 MDD I have to play it in software rendering or the graphics glitches become unmanageable). Obviously pure software-rendered games don't have a problem but there's not much rendering advantage then either.
I prefer to use my MDD for heavier OS 9 crunching tasks like Virtual PC or CodeWarrior. Relative to the MDD, the 7300 is smaller, more reliable and generally quieter, though the OrangePC card and Sonnet G4 have their own cooling fans (but nothing on the MDD wind tunnel howl). But you have to do some upgrading to get it to the point where it does well, and that will certainly cost more than an MDD, or even a DA G4 or Quicksilver.