I deliver full resolution (up to 22 MP), Jpeg Quality 11.
Additional every picture in 1920x1080 (Jpeg Qual 9) for HD-TVs and emailing. I think, this is the best solution.
This way my clients gets full quality. They can order Posters, huge walls or whatever they want to do. And they can quickly show the pictures to others with the downscales 1920x1080s...