I think the single greatest advance in jeans technology has been the introduction of a lycra/cotton blend - covers a range of 'defects' then! And very forgiving of increase/loss of a few pounds as you go along.

Totally agree with the points about the 'low-rise' concept - completely wasted about Ł60 on a snazzy pair of Bodens last year that kept sliding down over my hips - don't have a particular muffin-top problem (though Twiggy I ain't) but I still found them the most uncomfortable item of clothing ever to roam the planet.