There are wiser heads on this topic than mine, but here's what I've found.

Looking through a few MSDSs for the silicone spray lube, it appears the active ingredient is polydimethylsiloxane. Same for the silicone grease lubricant.

http://en.wikipedia.org/wiki/Polydimethylsiloxane
http://en.wikipedia.org/wiki/Silicone_grease

The spray lubes have mostly light hydrocarbon propellants (and a few proprietary odds and ends for voodoo purposes).

For the greases, there are a LOT of formulations. Everything from food grade rubber gasket lube to dielectric grease to heat transfer grease. Not all appear to be designed as lubricants.

I can tell you that the automotive dielectric grease I used to lube flashlight o-rings was scurvy stuff for that purpose. Great for battery posts though.

EDIT: Here's a link for a company that formulates all sorts of stuff. http://www.novagard.com/compounds/Rubber-Plastic-Lubricant.html To the right there are technical data sheet links that make interesting reading (to me, anyway). Standard disclaimer.