Most of my tubes have a few patches. I always try to distribute my flats so the tube stays balanced. Ideally I suppose you'd want two opposite the valve stem.
I once complained to a guy at the LBS about self-stick patches; that they would only last about long enough to get home. He looked at me kind of funny and said "well yeah, you'd never want to ride longer than that on a patched tube anyway." I'm more a "wear it out" kind of guy, and after that I use them to tie up x-cords, tie stuff on the roof rack, and a bunch of other stuff.