I'd like to thank everyone, but here's some that stand out for me:
Andi06: Junction Kit, buses, GWR railcar, and more!
PEV: For his tools, of course! Mesh Viewer and Texures2TGA are the most frequently used by me.
Eldavo: His scripts, Couplestar and Chameleon in particular
pcas1986 (Paul C.): The WIP Big Bertha model, and for his help in Blender
Skipper1945: Beautiful steam locos, but I'd like some LMS and less GWR please!
Paul Hobbs for his wonderful UK locos and rolling stock, most notably those in TC3 and the SnC add-on.
captainkman: Oh, wait...nevermind...:hehe:
tlblade: For the Lickey Incline route (despite the many spelling/grammar errors in the description!), which Paul C's wonderful Big Bertha model will be used on soon
lielestosbrat: Great freeware locos, and the Steam MPD route, based on Carnforth Sheds, which may feature in a music video shortly.
kemplen: For his wonderful vehicles, the ones in TC3 and SnC most notably
Sawyer811: Well, not for content, but for the great chats we have on Saturday mornings!
And I'll come back woth more to add to the list later!