I have always used staples brand paper but have noticed recently that despite the markings (96/20) remaining the same the paper seems thinner. It is now jamming my printer (also purchased at Staples) and previous to the last two boxes this was not occurring. My colleague has also noticed a change in the feel of the paper.
It doesn't claim to save the Earth but it does make for great printouts on my laser printers both black and white and color. It's often on sale in the $25-$30/case range and a good deal at those prices.