I just ordered a new chain/sprockets today.. (DID xring) and am planning to lay off the WD40. I normally use WD40 exlcusively for my dirtbike chains, but all the talk of it sneaking past the orings and dissoving the grease has gotten to me. I have a couple cans of "dupont performance teflon lube" that I'm going to go with and plain old kerosene rag and brush to clean it with.. By this time next year I'll be able to tell you if there's anything to the WD40 bashing.
Don't buy into it. Honda lubes, Yamalubes Maxima etc...all extra doe for the big guys. WD-40 is cheap and effective as a lubricant/water repellant. Only guys bad mouthing it are the ones that feel like suckers for buying $8 cans of chain lube for years. When I first got my XR I used lube...wore the chain out, got a new chain...used lube wore out...got the same chain this year used WD-40.....minimal stretch and the chain cleans up easy and looks nice. And yes I know how to adjust my chain and what proper slack is. This is just my experience and I'm sticking with the WD-40. I've talked to more guys that have switched and won't go back. By the time you blow the doe for a year on lube you could've bought a new chain.