I find X-scream quite boring, I rode it at the IAAPA trade show before it went out on the road (though I also rode it agian a year later in the are and it didnt change my opinion.
However a new Zipper costs in the range of $450,000 brand new (though technically Chance has stopped production of the Zipper (though if you went up to them with a wad of cash, they would certainly make you one, unlike Chaos which is DEAD and Turbo which they wont admit they ever made in the first place)

Favorite Wood Coasters: The Voyage, Ravine Flyer II, Thunderhead, Balder
Favorite Steel: Voltron Nevera, Steel Vengeance, Expedition GeForce, Olympia Looping
Parks visited: 232, Coasters Ridden: Steel: 894, Wood: 179, Total: 1073