Anyway, I've not replied to Bush, but my favourites are split between the Barley Mow 26, 777 and of course, the 638.
Some great memories of the 231 and 194 as I got older.
For specific sections of routes, that means the top deck of the 183 and Whitehall Road plus a (very niche) late running VR going between Wrekenton and Portobello on a 725/6.