For my preference I went for the 105, down to the focal length, I wanted a lens that would stay on my camera more, and i felt with 70mm I would be changing lenses more so than with 105mm, that little bit more from 70-105 does a lot for me!
I would struggle to say which one was better, as they are both brilliant lenses (have used both), but both quite different. My opinion anyway!


Myself and a mate of mine take pictures indoors perfectly with the 24-105 lens (weddings).


My ideal personal situation one day will be 5D with 24-70mm, and say my 50D with 70-200mm, no worry to change lenses then!
Unfortuantely, I didn't have enough money to get all I wanted in one go! So i compromised with the 105.


Hope that makes sense as to why I went for the 105.