I recommend Bick4. I might have been one of the first to recommend it...quite a ways back in this thread. As far as waxes or polishes are concerned, I use cremes very very sparingly or not at all on my own shoes and Angelus wax when bulling, but only on the toe and heel--where the leather doesn't flex. But I don't really think it matters--they're all somewhat occlusive and equally bad for the reasons I mentioned above..
I think probably the best advice overall is simply to brush your shoes daily--keep them clean
I agree and also use Bick4.
For polish, I mainly just use creme polish. I've used Saphir as well as Meltonion and haven't had a problem with either, even though the Saphir gives more to the pigment of the shoe.
I only use wax on the toe and heel as well because the leather doesn't flex and these are the areas that commonly take the most direct trauma to the shoe when walking.
In the end, keeping the shoe somewhat moisturized (like human skin), protected when not being worn (in a shoe bag), and brushed before and after wears (to remove dust and dirt particles) are the most important to keep the shoes going on as long as you can.
The rest basically is just making them look better with more pigment and a nice shine!