I've found that the best grease for all-purpose automotive use is that Mobil-1 grease that comes in the tube and fits in your grease gun. Not that it's some magic formula or anything, just that it works well as a bearing grease as well as for fittings and such. It doesn't degrade polys in my experience and it comes in a handy pink color so it's really easy to tell if it's gotten hot or become contaminated.

I hadn't been able to find it for a while, but I noticed Kragen's is carrying it last time I was in there.

I guess I'll have to go buy another grease gun since my old one is now in use at work using company purchase moly grease.

Clay