As Kaitlyn said, cast iron is clearly the best type of skillet.
There is little debate among serious chefs that cast iron makes the best cooking surface for most tasks. This is because it is thick and heavy. When used properly it is almost nonstick.
The problem is that the rest of us don't want to clean cast iron and usually don't use it properly.
When it comes to even heating, I will agree that cast iron is second to none, but I'm not sure that all chefs would consider it the ideal cooking surface -- most chefs prefer something that gets hot fast and can cool down fast if they remove it from the heat. What they want is control.
I used to use cast iron exclusively until I got into more 'gourmet' style cooking that involved saute-ing, de-glazing, and reducing sauces. The cast iron simply took too long to heat up, and once hot, I didn't have the kind of instant temperature control that I wanted -- once you get cast iron hot, it stays hot. The advantages that copper, aluminum, or stainless clad (or tri-ply) pans have is that they are more responsive to temperature changes -- you can reduce heat or lift the pan off the burner to adjust temp, or turn the burner back up and get instant results.
Cast iron does have its place, but for most of my cooking needs, I'll stick with thick aluminum or stainless 'clad' pans. But I'd take cast iron over a pan with a thick disc in the bottom and then thin sides -- I hate those types of pans.