Product review (5 stars): Piece of Cake!
I ordered this Culligan generic fridge water filter based on other reviews here, and here is mine.  Super simple to install is what I like, and is what this was!  My wife's first instinct was to call the plumber to install this unit, and I informed her that our plumber was the person who suggested we get something like this so we could do it ourselves!  We did it, going by each detailed (but simple) instruction.  We already had the plastic water line going to our ice maker, but no filter.  There was also no shut-off valve, so our plumber told us to simply double up the line to stop the flow (like we did the outside water hose as kids), and that worked perfectly.
Simple and easy installation.  The hardest part was getting the 2 screws lined up fairly even on the wall to mount the thing.