Hi TS, I'm another prime lens lover here, but not because I'm lazy to zoom :bsmilie:
I like prime for several reasons. The main one is because I like to move closer to the subject, check the interesting part of the subject and shoot from the angle I find odd but nice. Secondly prime lens gives me the extra edge of DOF control and sharpness at wide open which let me isolate the subject from the background nicely and sharply. It also allows me to shoot at some low light situations without using flash.
Third reason is the light weight of prime lens compared to the trinity zoom 24-70mm and 70-200mm. I can carry my gears and shoot for long hours without feeling tired.
Ya there are some disadvantages for prime like what mentioned above, but they haven't happened or created problem for me so far because my legs manage to do the "zoom" :bsmilie: