I'm looking to get an Aimpoint, but not sure exactly where/how I want to mount it.  Whether it be as far back as possible, over the delta ring, midway up the flattop upper, etc.  What are your opinions on the best place to mount it and with what kind of mount?  

many many options, larue, aimpoint, kac, arms, cgg

Most seem to like it over the delta ring.  Personally, I like mine on the handguards just in front of the delta ring.  Someone had some pics with them at the end of the HG just behind the FSB.  I've seen them on the tops of carry handles.  There really is no wrong answer.  Figure out where it works best for you and leave it there.

I would recommend cowitnessing with irons if possible.

Good Luck