What's your favorite polish?

[Frodo]

+1 on Aquawax. Quick, easy, and adds some pop.
Haven't tried the other products discussed, so can't comment on them. Been tempted for years to try Zaino...but have been happy with what I've been using so haven't so far.

[Slate 01]

Zaino only on my vehicles. Try the Leather In a Bottle as well, awesome products.

[j.fro]

Cool topic!
For jobs that take a more aggressive polish, I've had great success with the Griots polishes numbered 1-4, with #3 being the best all-around compound. For a less aggressive polish, I've liked the P21S Gloss-enhancing Paintwork Cleanser.
For a final wax on a daily driver, Meguires NXT does a nice job of staying shinny and on the car for a long time.
For final wax/ deepest shine on something that doesn't see much rain, P21S Carnuba works great.