Here's the easy way to restore the look and feel of your wooden deck. No sanding! This also works to improve the look of your cement patio. We have the step-by-step instructions on how to use Restore 10x Advanced on The Home Depot Blog.
We wound up using Behr solid stain in Slate. We chose it because of its scores on a Consumer Reports test and we generally have had good results from Behr products. Our deck "after" painting. We liked the effect of the old Behr semi-transparent Redwood color showing through, so we left it.