I have the 17, 90, and 24 II. The 90 is most useful for macro and product photography. I occasionally use it for landscapes when my subject is more distant or for occasional city panos.
The 17, as already mentioned, is most useful for interiors. It can be useful for landscapes if the scene lends itself to such a wide angle. It is a very sharp lens but has a serious tendency to flare. You have to be very careful with it if you are in the presence of any lights or the sun in particular. It is therefore a very poor choice to use for sunrise/sunset shots.
The main advantages the 24 II has over the 17 are
- Much better flare control. A very good lens for sunrise/sunset shots
- Much easier to use filters. You can technically add filters to the 17 using special adapters, but both the adapters and the filters are pricy.
- Closer focusing distance, allowing more of a macro effect. This is very useful for objects very close.
I primarily use my 24 for exteriors and as a walk around lens. On vacation it is my most used lens after my 70-200/2.8 II. The 17 is a great lens, but the 24 is more flexible due to the above.