If you could have only one lens to work with your entire life, what focal length would that lens be? 35mm? 105mm? 200mm? It sounds a daft question but I've noticed over the years that i take the vast majority of my images around the same focal length settings.
I'm a wideangle photographer mainly using 35mm or wider for a lot of my imagery. I just love the depth that you can get with a wideangle lens but others prefer telephotos, macro, super wideangle fisheye or just a standard 50mm lens to shoot the majority of their images.
My favourite is the Nikkor 35mm f2.0 which i use quite extensively but i 'm currently on the lookout for a wideangle zoom around the 18-35mm range. It should be interesting to see what i do with the wider angles available on that lens.