Everyone who loves house music knows many tunes that made the hair on the back of their neck stand up when they first heard them. When that tune is still doing it 20 years later you know it's a bona fide classic.

Frankie Knuckles created other great house music, but this is surely his finest hour. The piano riff alone is worth the price of admission (see SL2 - DJs Take Control), but when combined with the bassline, overall production values and that vocal, it's a credible candidate for best house record ever. And it was made in 1987.

Classic Frankie Knuckels song.
Still sounds as good and fresh today as it must have back then.
Regardless of all the good music being produced nowadays, House just doesn't evoke that mystic feeling anymore.