The only real solution, I think, is stronger tires -- slime and Mr. Tuffy are just "band aids" that fail to address the root cause, which is tires optimized for recreation, rather than utility.
I'm beginning to feel that you can never have too many tire "band aids," as long as each one actually helps at least a little. I used to get piles of flats. I got a kevlar-belted rear tire AND am using a Tuffy liner; it's still been punctured twice in the past 1000 miles or so. (front tire has Tuffy liner but is not kevlar-belted and has had 1 or zero flats in the same time.)