Personally, I just use Spanish or yellow onions for my French Onion Soup. The key to really good French Onion soup, IMHO, is in properly caramelizing the onions. I agree with Chrose, I don't feel it is neccessary to cook the onions for 2+ hours, but it will take a good amount of time to develop the proper amount of caramelization. This is were most people fail. They either don't caramelize the onions enough, leading to a weak flavored soup (again IMO) or they try and hurry the process resulting burnt, bitter onions. I look for a nice rich brown color and usually deglaze the pan a couple of times with just a couple tablespoons of water to keep the bottom from burning. As for the wine, I have discovered that I like a 50-50 mix of sherry and red wine for my French Onion Soup. I first deglaze and reduce the sherry, then add the red wine and reduce that. My soup also contains beef broth, garlic, thyme, salt, and a hefty dose of black pepper. For the bread I like toasted French bread and topped with either Gruyere or Swiss, and lots of it.
I also make a wonderful creamy onion soup that is basically the recipe above with added cream, thickened with a roux and finshed with Gorgonzola cheese stirred into it. Not traditional, but absolutely heavenly.