I think I just have a love for railroading exotica - at least, stuff that’s exotic to me. The clean designs of British locomotives have always appealed to me in the same way that the simple, clean, sleek lines of a Jaguar XKE or Aston Martin have. Gresley’s designs are particularly, eherm, attractive, and I’ve always liked the Morgan-like staunchness of the GWR (even if it was originally started by the Victorian Elon Musk,) and the Lotus-like inventiveness of Bullied’s Southern designs. LMS’s constituent companies were more interesting to me than what they became, though I appreciate Stanier’s drive for reliability and power. and that his design was my first HO train.
 
As for stuff that’s “Local,” a couple of my favorite locomotives in my general part of the country are Chinese - former IAIS 6988 and 7081, formerly China Rail 6988 and 7081. Granted, that’s partly because those two were the first mainline steam I’ve ridden behind, but they’re still big, lumbering things that make a good show. If only it weren’t so difficult to get HO scale QJs in the US…

Lookin good. Your on the right road, Bob, with british designs!

@Dr_Robotpony
 
Yeah, I feel you bro. German designs are only my favorite overall, I’ve got all kinds of subcategories and technicalities to fit everything else.

@JustLikeTheNewGuy  
I’m one of those people who can’t pick from all the great designs out there, there’s so many good looking engines out there that it feels almost impossible for me to choose.

@Bobthedalek
 
Nah, I’m not annoyed. There are so many different ways to design a steam locomotive that it really comes down to personal preference to say which is “best.” For me, personal preference says German, for you it’s British, and for someone else it may be Russian stlye or something.
 
However, I will admit that Maid Mareion up there is pretty cute.

@JustLikeTheNewGuy  
I’m probably going to annoy you then when I say that I prefer British Engines for the lack of external piping :P it gives a more dinfinitive shape to an engine, and I like that :)
 
That being said though, there were a couple of American designs that were imported to England that I do think look quite nice. The first being the 0-6-0 tanks that worked in Southampton docks from WW2 onwards (replacing the LBSCR E2 tanks), and the narrow gauge bawldwin engines. There used to be five of the latter that used to run on a railway that lay near to where I live (Ashover Light Railway) well worth taking a look at ;)

@Background Pony #C35C
 
Yeah, but American steamers looked better. All of that exposed piping. British locomotives are too smooth.  
But for the ultimate in steam locomotives? That would be German or French designs. Plenty of color (some of the French ones especially,) and lots of neat details (piping, pistons, ect.)

The “Maid” reminds me a bit of Skarloey from “Thomas the Tank Engine.” The small, early steam engines certainly have a bit of appearence to them. British steam engines always had such nice color schemes compared to American ones (mostly because after the 1800s virtually all American steamers were black).