Everyone has a favorite so you will get a bunch of replies, however.....
I use ProGold MFR Chain Lube. It is clear and doesn't build up on the chain. But what really works for me is not what I use but how I apply it. When you spray any lube it goes all over the place and quite a bit is wasted. I put the bike up on my lift, remove the chain guard, and if the chain is very dirty, I clean it first with a rag soaked with kerosene. Then I dry that off and get another rag and soak it down with lube (actually, I use old tube socks). Then I slowly rotate the wheel and use the rag to lube the chain. It makes for a much cleaner job and less mess to clean up afterwards....
