Aside: given how much mainstream attention MAME is getting, I wonder how long until the owners of arcade ROMs start selling legitimate copies of them, in MAME-friendly format, over the internet. A while ago, they tried selling arcade games wrapped up in proprietary Windows-only emulators, though that doesn't seem to have been a resounding success. If they had a web site where for a few dollars you could download a ZIP file of MAME-ready ROMs (and possibly ancilliary artwork and such), I could see a lot of people (including myself) using that, and it making quite a bit of money for the owners of the ROMs.
But of course it will never happen; everybody knows that selling digital content without watertight digital-rights management (which is incompatible with an open-source emulator) is No Way To Run A Business.
what a rip off price! my boyfriend built one for about half that price... well he took an old machine (that once housed circus charlie) and pulled it guts out to install mame in it.
as for roms, companies like atari i think even supply roms for old/rare games with new versions of mame emulators, and there are a number of trading trees that can burn you full sets of mame roms (like 3000+ games) for the cost of the blank cds. you can also paypal some dude in the states for a "nominal" cost (but his postage prices are quite hefty). freemameroms.com i think