I don't understand MAME at all. Seemed like a good idea until I found out that I can't get the ROMs anywhere.
http://www.romnation.net/
or
http://www.rom-world.com/
Though Warning, They both have porn ads on their sites and they make you vote for their site as a top gaming site before they let you download any ROMS
That's 'cause it's illegal. This one site had all the ROMs, but they made the wrong people mad, and they got turned in and their ROMs were pulled. I haven't looked for MAME ROMs in a long, long time, but I am quite sure the ROMs are out there if you know where to look. There was a burners club--Tombstone was in the name, I believe--where you could send people blank CD-Rs, and they would return them to you with all the ROMs (never would trust that, myself). And, there are ROM groups in Usenet.
Anyway, my game playing goes back to the '70s, but I don't limit myself to old games. One game I really responded to, for some reason, was a Western shooter called Sunset Riders. I loved it in the arcade, and I played it constantly on MAME. It's basically Contra in the Old West, if you know the reference.
Other incredible shooters are the Metal Slug games. Except for the PC's Duke Nukem: Manhattan Missions, which I adore, the Metal Slugs are probably my favorite shooters of all time. Another SNK game I really took to was called Mark of the Wolves. And, I don't usually like fighters.
The best way to get Mame roms is via the Free MAME Roms society at http://www.freemameroms.com/ Very easy to get a full set.