I use the rigid corrugated clear pvc panels for the sides of mine... I've attached them with eye-screws to the wooden battons of the run...they are very solid,rain, wind and fox proof and my buns can see out, they also don't get any rattling or tarp type noises. The eye-screws i screwed in by hand after making a small drill hole in the pvc and so can be easily removed in spring.
I got my pvc panels from Wickes... about 8 pounds a piece (5 ft by 3 ft approx.) I wouldn't use anything else now, they can be cut to size ( if careful ). They look good too, as I was worried about the 'eye-sore thing'... I live on the edge of the Peak District so get very high speed / strong gusty weather here.. they work a treat on mine and I wouldn't use anything else now.