For more than 2 years I've been using Canon DSLR cameras with the smaller APS-C size sensor rather than the 'full-frame' sensor that is about the size of a 35mm frame. While I wouldn't quarrel with anybody who chose to go with the larger sensor, I made a very deliberate decision to go with the smaller sensor.
One reason that I chose to build my system around the APS-C sensor is that the lenses used with APS-C have shorter focal lengths for equivalent fields of view than the lenses made for full frame sensors. The advantage is that the shorter lenses have greater depth of field, everything else being equal.
I do a lot of landscape photography, and extra depth of field is a big advantage, especially when shooting scenes with wide angle lenses where I need to focus on the near foreground as well as the horizon.
