Thanks everyone. I re-putty'd it today and it seems to be holding water. I thought about going the double gasket route but didn't know if it would work. Seems like you'd have to use some sort of sealant on the gasket/tub mating surface, and maybe even on the gasket/drain surface.
So I guess I'll be carrying plumbers putty from now on, and Goop, maybe a spare drain assembley, some 1 1/2" rubber gaskets, 14 sizes of pipe wrenches, an assistant......
Be prepared!