It's pretty much the same with Colorado, isn't it?
Most people here in Germany, for example, will always pronounce it Color-aah-do, and I've even heard English-speaking persons doing so. The correct pronunciation of this state, however, (I hope I don't blunder now) is Colo'rædo.
As it is situated in Nevada, and if you don't mind, I'd like to ask about the city of Las Vegas, too. Most (if not all?) pronunciation guides give it as 'Lahs Vayges' (Vay like 'way'). But, when I hear Americans pronouncing the name, it sounds to me much more like 'Lahs Væges'.

Which one is right, or more widespread in your opinion?