Well, I won't be the one who says that Mike's full of it. If you really need a 400 speed B&W film, you can't really do much better than TMY-2. Don't get me wrong, Delta 400 is pretty darned good too, but I just like TMY-2 better. Could it be because I'm more familiar with the way it works? You bet, but that's not the only reason. I like it because it has the ability to capture detail over a very wide brightness range and has a grain structure as good or better than some films that are two stops slower. Obviously, TMX will have even finer grain and even more resolving power; but the point is mostly moot. Grain only begins to show up with really huge magnification when viewed at normal distances. The film's resolving power is usually greater than what the lens is able to deliver.
Stock answer: It depends on what you want your architectural pix to look like. There is usually no one film that is best for any one application. There are, however, films that are better or worse at meeting named criteria.
My personal answer: For most daytime b/w architecture pix that I would do for my own work, I would probably use Rollei IR400, if the budget allowed. I would even use this film over any slower film, in most situations. It is sharp and contrasty, and due to its extended spectral sensitivity, can be highly tweaked with filters.
So, what are the criteria for your pix to be a success in your eyes, what format are you using, and how large will your prints be? Black and white or color? (I assume b/w, since you mentioned a b/w film.)
Off the top of my head, there are:
Kodak Tri-X 400
Kodak Tri-X 320 (discontinued, but still available in retail locations and through various Internet sources)
Kodak T-Max 400
Ilford Delta 400
Ilford XP2 Super
Fuji Neopan 400
Rollei IR 400
Kodak Portra 400NC and 400VC
Kodak Gold 400
Fuji Pro 400H
Fuji Superia 400
I'll put in another vote for TMY - I've shot quite a bit of architectural work with it and have always been pleased. That being said I now typically lean toward a slower speed of film. TMY is nice to use though, I agree and I find the 'edge sharpness' (or however you might say it) to really lend itself to sky-scraper lines. I've always developed it in Rodinal so I don't have much input on what the best developer would be...except to say that I've been happy with 400 TMY & Rodinal at 1:50.