You need art. Find pictures of street fighter characters from at least 3 separate games, the dinos from bubble bobble, Sonic the Hedgehog, and your favorite band/sports team/movie logos. Top it off with a big MAME logo and Call it MameCade. If you prefer, Opt2Not will draw everything by hand for you for $50.
Next step is to get a 10 terrabyte hard drive and download every game ever made. Hyperspin will make it all run. You will have ultimates machine and friends will play, but only if you have cool carpet and ninja turtle bedsheets.