Retro Gaming is all about the nostalgia factor... games of your past. However, I have found a lot of very interesting games just searching through older ones. A specific example I can remember is a game that was on the PC I was introduced to called: "Arcanum: Of Steamworks and Magick Obscura", a game much like Fallout before somebody decided to make it a first-person shooter. You could have also tried like NHL 95 on the Genesis or Shining Force III, Final Fantasy Tactics, Ultima 4-7, Goldeneye, UFO: Enemy Unknown (now called XCOM: Enemy Unknown) or something that has some kind of unique element to it that other games have copied since their release.
Instead of the Neo Geo, which umm... you're the only person I know who has tried it.