I really do love the 85mm 1.8. I just thought it would be over kill some I have the 24-105. I mean if I need 85mm why not just use the zoom ? I guess if I had a low light situation right.
You need both LOL
The 85mm 1.8 is it's own beast. The 24-105mm is a very sharp versatile walkaround lens. It's versatile because of the range and f4 + Image Stabilizer let you take decent pics in lowish light. It's nothing compared to 1.8 though, and the bokeh you'll get with it.