Whoa, first off, back off MLK. I agree that the games may indeed be easy to find, but I've seen both the simpsons and x-men go for quite a bit of money on ebay. So please don't get too trigger happy.
I'm not fond of the idea of emulation, and I won't emulate and unless something like the Sega Smash pack or Atari Anniversary pack comes along, I don't go for it. These games are made by the licences for sale again. For me, it's better to get the real game and play it how it was meant to be played. I've gotten around the cabinet situation by buying a Supergun. It's worked for my NEO, Capcom, and Neo 64 cravings.
I totally agree with Mystery anyway. MVS is much cheaper than AES, and some games are only available for the MVS (and I'm sure AES likewise). And the disclaimer on the ROMs is that you are supposed to own the game and system before emulating it. If you really want an AES, go look for some desperate person that is just trying to pay some bills, he might have one. Try visiting those flea markets, while some of them may be nasty and filthy, they do hold stuff that works, if you know where to look.