I know a lot of what I do to my leather products would probably put most of the ladies on this forum into shock or cardiac arrest, but it really is a tough material that is used because it can take a beating. I've been in the equestrian world a lot longer than the handbag world and have found that the methods I use to keep my saddles, bridles, boots, and strap goods in shape translates perfectly to most bags.
I love the Leather Therapy line and it's another great product that doesn't darken. Leather CPR is also a fantastic conditioner for leather that is dried to the point of cracking. It really plumps the leather back up to fill any cracks in and help it to regain flexibility. In terms of quality for the price, though, Lexol is my favorite. It comes in all sorts of sizes and won't break the bank either.
If ever are in trouble and you don't have a cobbler nearby, try a tack store. You're bound to come across some good advice from people who have plenty of experience cleaning and maintaining leather goods.
