I use the Nikwax Techwash and TX wash in. The idea they advertise is that the wash cleans the garment without compromising any existing water repellency/proofness. Then the wash in treatment basically applies a new layer of DWR all over the garments. As far as I can tell, also given the name of the company, it's some kind of low temp wax that embeds in the fabric, you can't tell it's there after the application but in my experience it works well. It does seem a bit pricey for the number of applications you get out of one bottle though. But I haven't used anything else because it was recommended to me and I've been satisfied so far. I wouldn't waste your time with the spray-on stuff from any company. I'm also curious to hear about any "homebrew" options...

http://www.rei.com/product/783563/ni...rwear-care-kit

Looks like it's just a couple bucks cheaper on Amazon, but if you buy from REI and don't like it, at least you can get your money back.