Zune or iPod?

In light of the Zune update that brings a few very interesting features, the choice between an iPod and a Zune is not so clear-cut. Do you go with the one that has iTunes Store support and more accessories, or do you go with the one that has Wi-Fi syncing and music rentals? What do you pick for your next player, and what would you pick if you were in the market for your first player?