I like,
Amtrak shamu on the P42's
NYS&W's yellow jacket
KCS Belle
Florida East Coast pre railamerica
Erie Railroad green with golden wings on the nose of a E8A
Erie Lackawanna Grey with maroon and yellow
NYC Lightning bolt stripe
But mostly a fan of these guys as I am trying to model them.
There is/was a small railroad that used a light gray body color with a dark blue/purple band around the whole locomotive at 'name badge' level, similar to Susquehanna's style. It was beautiful and I haven't been able to find it again
I second that
Southern Pacific Daylight color scheme just looks great to me. That's why I bought one a few years ago in HO scale: Bachmann #4446 GS4 Daylight with smoke.
-Art