I use Hoppe's #9 as a bore solvent, Gunscrubber polymer safe for general crud blasting, and I mostly use CLP for lube, but I've been looking hard at using Mobil 1 5w30 synthetic, based on members' recommendations in here. All of my cars use it anyway, and I keep a utility oiler of the stuff around for the kids' bikes.
I learned as a teenager that WD-40 builds up and gums on skateboard bearings. You can get away with using it a little bit if you live in a VERY dry climate, but I would say, only in an emergency, followed by immediate thorough cleaning at the first opportunity.