Well you're preaching to the choir. Of course a lot will depend on where you are touring. A trans-Siberian trip will probably require more gear/spares than a trip across the USA where a 7/11 is usually within a days ride.

I firmly believe that a gear list with weights is a good place to start. Yes I know it's really geeky and you will be called a weight weenie, but it works. It makes you consider the use of each item and where you can make weight savings. This really brought home to me the big weight savings you can get by going from a steel sport touring bike weighing 25lbs to a CF endurance bike at 19lbs. I iterate my list each year and often remove something.

One advantage of doing all this to reduce weight and number of items is that it makes camping more efficient. You can set up and pack up quickly and you aren't lugging loads of stuff around. I'm so happy that I can easily lift my bike and gear up if I ever need to get over obstacles, up stairs or use public transport.

For years I though that 50lbs for bike and gear was as low as I could go and be comfortable, now that weight is between 30 and 40lbs.