I use Rain-X. I know there are numerous Rain-X haters here, but the stuff works great for me.
Rain-X is a mixture of Silicone and Alcohol. When you spray it on the windshield, the alcohol evaporates as you rub it in, eventually dissapearing, leaving only silicone. The silicone fills the chips and scratches, leaving the windshield slick and smooth.
After Rain-X I can't even see the little chips. And lasts weeks to months.