Ok, thinking of getting another lens but I don’t know which one would benefit me most. I have been looking at the Canon 15mm 2.8 fisheye but I don’t know how often I would use it, although it does look pretty cool. I shoot a little bit of everything (landscape, people, etc.). So, any suggestions other than the fisheye? Any arguments for/against the fisheye? Thanks. See sig for what I have already and please, no 300 2.8L...I am still dreaming of that one but it aint comin any time soon. 

there is one small open spot left in my Photo Trekker backpack, just lookin to fill it. 
