I ordered the 'ice breaker" from gutter glove http://www.gutterglove.com/
for a 15' section over my front door entry. Have not installed them yet.
Very expensive, so I hope it does the trick.

For the rest of the house I went to Menards and bought the plastic 4' pcs ($1.68) that also have the screen atop the holes. Very simple to install, needed a putty knife loosing the shingles in a few spots.

After cleaning out the gutters 3 times this spring, I figured I'd give them a try.