For my 20D that I intend to purchase, I am having an excruciating,
painful time trying to decide which lense to put into my outfit.

I like the 100-400 in that it has IS, and of course, zoom.

I like the 400 5.6 because it is prime, sharper lense, etc.

I saw numerous pics posted on various websites for each lense. They
are all outstanding (the oustanding ones that i viewed).

I love closeups. I intend to do some birding along with other nature
shots. No sports. No archetecure. Pure nature.

So I need some more opinions on the 2 lenses plus some experience. I
sure do appreciate it!

Thanks
AC