Lexol works better as a conditoner. I suggest leatherique, especially if you seats are beginning to get a little hard in areas. It will bring them back to softness and take out dirt you can't even see. Its a bit pricy, but worth it.
a wet cloth... seriously though, I've used a lot of different products and they all seem to make the seat slippery or greasy looking. not to mention the fact that if you miss a spot here and there, those type of cleaners make the seats look like crap. I stick with a damp rag but also try to keep my ass clean so that I don't track anythin onto the seats in the first place!