One of the things that worked against my nimbleosity in the early years was fast glass. I couldn't afford it in the size I wanted. To get a relatively compact camera with an f/1.4, f/1.8, or f/2.0 lens, I would have to spend a lot of money -- like, Leica money.
I want these lenses because photography is most fun for me when the flash is off, and the aperture is wide open. Suddenly I feel like Eisenstaedt, W. Eugene Smith, or Cartier-Bresson. The urge to take pictures with a prime lens in existing light is engrained in my photography DNA.
For a long time, I had to make do with DSLRs or slow point and shoots. Then Micro Four Thirds and the Compact System Camera revolution hit, and I could have speed I wanted at a price I could afford.
I'm thinking about this right now because I spent most of the day Saturday shooting with an OM-D and a 75mm f/1.8 lens... wide open, of course. I was working with Nimble Fit Kit #11, and loving every moment. My two current favorite lenses for the OM-D are the 75mm and 17mm -- both with a maximum aperture of F/1.8.
I'll probably never own a Leica rangefinder with a bag full of their beautiful optics. But I feel lucky that technology eventually saved the day and fulfilled my desire to feel like a modern Life Magazine photographer, while still being able to pay the rent.