What kind of material is your favorite row cover fabric?

What is your favorite material to use on hooped rows of vegetables, or as a floating row cover, and where did you buy it? :)

We use Agribon is two weights - a light weight for summer transplants and a heavier weight to wrap the citrus trees in winter. Our local organic gardening supply store sells it by the foot. We found it cheaper to buy a bolt of the fabric from Peacefull Valley Farm Supply (www.groworganic.com).

I use polyethelyne. plastic sheets taped together over 10 foot 1/2"pvc stuck on 3 foot rebar.. 2 - 8 mil sheets.. 1 sheet in oct- dec and march 2 sheets jan - feb.. eat from the garden pretty much all year - zone 6 the pic is the salad garden around easter.. and a little of my cat boo..