The most difficulty I've ever had mounting a tire was a 23mm Bontrager (kevlar) on a Campy Proton wheel. My brother and I broke many tire levers trying to mount it, and once mounted it was so tight you couldn't even wiggle it around to make sure the tube wasn't caught under the bead anywhere. So every time we inflated the tire it would go flat within minutes from being pinched. As a result those wheels have never been used. My brother also has a set of wheels with early '90s Campy rims and they are almost as bad. Is it a Campy wheel thing?
I've found the easiest tires to mount by far are Panaracer Paselas, and I also prefer the way they ride to any other tires I've tried. And don't forget, skinny tires are usually harder to mount than wider ones. I've never mounted a 23mm tire without at least a decent amount of effort and trouble, but 32mm Paselas are almost always a breeze. And 26 x 1.75" Paselas almost mount themselves.
I do have some 26 x 1.9" Hutchinson Acrobats on my rain bike, and they are pretty darn brutal for being so big. Next time I'm getting Schwalbes for it.
I've also had fairly good luck with this:
http://www.universalcycles.com/shopp...&category=2120
It's not perfect, but it's definitely worth a few bucks.