Oddly enough, my fave at the mo is one of the really early MSTS (No, not "Scotsman!")
It's a Johnson 4-4-0 reskinned into M&GN yellow/brown colour. A bit selfish, but a nice mover!
My favourite's gotta be the WSR Manor- Great model & perfect sounds.
Only complaint is that by default, it seems just a little underpowered for proper mainline running. (I only ever managed to get it to 80mph, double-headed with 12 coaches on Paddington to Penzance)
My reskin of Reg Furniss' Vale of Rheidol Tank loco, into what it appeared oin the early eighties will be uploaded soon, after Reg uploads hisd updated original model