I used to use those half-inch wide throw-away $2 fiberglass filters on my old furnace. But when I invested in a high efficiency furnace, I decided to go with better air quality in the house, too. Boy did I get it.
My Filtrete 4-inch wide furnace filter traps a lot of stuff I don't want in the furnace, no less the air I breathe. I have a dog, and though I keep her groomed, there is still dog hair left over; the filter is doing a great job filtering out dog hair that would otherwise enter the furnace air supply. It's a comfort knowing my home is a little cleaner and the air is a lot more breathable with a high quality Filtrete filter.