I use this stuff b/c it's the Park PolyLube but at a fraction of the price.
Lucas Oil Products X-Tra Heavy-Duty Grease (1 Pound Tub)
Park PolyLube is pretty good, too, but too expensive. Basically, as others mentioned, any ol' grease will do for most bike applications. I do demand something higher temp for coaster hubs--most HD bearing grease will work for that.

A lot of ppl like white lithium grease for bike stuff, but I find that it smells realllllly bad once it's contaminated, so I kinda hate it. It works pretty well, but it seems to break down more quickly than some of the higher-end options..... maybe I just think that b/c i can smell a stank fishy smell coming from riding buddies' headsets sometimes.