I've always used contact cement. It works incredibly well but there is some draw backs. Being an oil based product, you need to use it in a well ventilated area (or not :drool: ) and it tends to make certain types of tolex stretch. The problem with stretching is that it contracts as it dries, therefore, it's more difficult (not impossible) to get tight seems.
I know there's some water-based products that work great, but I have yet to try them. I believe Mojo and most places where you can find tolex sells it. When I've used up the remainder of my contact cement, I'm going to try the water-based stuff.