Badr Alomair of Madman's Cafe was talking about the music from Fatal Fury, and I took the opportunity to remind him that one of the themes from the first game was borrowed from Street Smart, a fighting game SNK designed shortly before the Neo-Geo was released. Here, have a listen:
Fatal Fury: Sound (Sandy?) Beach theme
Street Smart: City Streets theme
The Fatal Fury track is a little fancier thanks to the power of the Neo-Geo, but it's definitely the same tune. (Pretty catchy too, now that I think about it!) Beyond this track and the option to double-team opponents in the versus mode, the ties between Fatal Fury and Street Smart are pretty tenuous. However, there's still fan speculation that the latter game is part of the long-running South Town series. SNK hasn't confirmed this (or even seems to remember that Street Smart exists...), but hey, anything's possible.