RBY's Gym Leader theme is one of my favorites. So is the theme for Vermillion City. All other Vermillion themes are terrible. It sounds like it gets more and more sedate everytime it gets remixed. HGSS's Vermillion theme is just laughable.
Oh, can't forget Goldenrod City! Yay, Goldenrod!
Do do do, do do.
This makes me happy.