I'm a 50mm guy, too. I think that the 35mm lens shows what we see, the 50 shows what we notice at a given moment, and the 90 shows what we concentrate on when interested.
I think my preference for the 50 is influenced by two factors besides the perspective. First, in my impoverished young years, all I had was a 50 and a 90--a fast 35 lens was too expensive. Second, I find that whenever I shoot with a 35, I often end up cropping to a 50 magnification anyway. Part of that is that I wear glasses, and before I got contact lenses, I could never see the entire 35mm frames in a .72x viewfinder. Now that I wear contacts at least on weekdays, I use the 35 more.
Another issue is that I am 6'3" (190.5 cm) tall. So if I get close enough for a 35mm lens, I tend to tower over my subjects unless I get on my knees or crouch. So a couple of steps back and a 50 is often better.
I tend to use shorter lenses in places with skinny streets, like Europe. If I could have only one lens, it would be a 50. If I could have only two lenses, they would be a 50 and a 90. I'm grateful I don't have to choose, though. Sometimes, indoors, the 35 is the only game in town.
While I have a 21mm VC lens, I use it rarely. Enough that I'm glad I have it, but rarely. I think that wider than 28mm, the picture tends to be as much about the lens as about the subject. Ignore that last statement if you live in Europe, or within a day's drive of the Arizona-Utah border! 🙂
--Peter