I use Meguirs extreme shine. It is an aeresol that repels dirt well. On the LMM I just use simple green and wash the crap out of them. It is on the dirt 90% of the time so no tire dressing will stay looking good on it. 40k miles of wear and they still look brand new on the sidewalls.
I like the Black Magic foaming stuff in an aerosol...it's like $5 a can and it's easy to put on. When it gets on paint, it comes off better then other sprays I've used. I've used quite a few different types (I detailed cars in my garage full time for a summer, and PT over a few years) and settled on the Black Magic as the most cost effective, easiest to apply and had a good shine.
D.O.T 3 Brake Fluid. Seriously. I learned that from my buddies at the fire department. Its the "secret" tire shine they use when we enter our heavy rescue in parades. It doesn't have any harsh chemicals and think about it....petroleum product being applied to a petroleum based rubber. Makes a great shine that lasts.