We were shopping for a new canopy last year. We found that the majority are called shade canopies and are not claimed to be water resistant.
We bought the Gander Mountain Combo Canopy which is advertised as water resistant. It even has taped seams just like better quality tents. I used some seam sealer in a few spots where there was unprotected stitching. It comes complete with three wind walls and four sided screening. It has worked great and some friends have purchased the same canopy after seeing ours in action.
http://www.gandermountain.com/modperl/product/details.cgi?pdesc=Gander-Mountain-Combo-Canopy&i=760902