The Kai guy at DigitalRev is posing the question - if you are limited to just one of the two lenses, 35mm or 50mm, which one would you choose? My own decision is 35mm for a cropped frame and 50mm for a full frame camera.
Of course we have not taken into account the speed and price of the lens. In general, my readers know I prefer zoom to prime lens and my favorite walk-around glass is the Canon EF 24-105mm f/4L. Although it is a lens with an older technology, its quality and performance makes it a great value performer for me.