The Star Wars arcade game is how I discovered MAME, and emulators in general. I was searching for Star Wars-related games back in the day, and found some random site which had a bunch of rom files. I had no idea what they were, but I downloaded the Star Wars one and figured out how to run the program. I was absolutely amazed at what I saw in front of me, and afterwards started downloading as many roms from that site as I could. It was a whole new world open to me! I would soon discover other emulators, although back then they weren't that good (heh, I remember how SNES games could be unplayable unless you disabled certain layers).
I also played the hell out of Star Wars Arcade for the 32X. Goddamn, that game got hard.
I'd probably consider DDR to be my personal favorite arcade game, lots of good memories from that.