@Marlene -- this pair obviously runs to the more expensive end of things, but it's the best photo I've come across online that illustrates the concept of a "slouchy skinny":
http://www.jbrandjeans.com/pd/p/1616.html
I'm honestly not sure where to get them yet, I only started noticing them (magazines, women I've passed on the street) in the last month or so.
@April -- yeah, it sounded weird to me too the first time I heard them described that way! it's strange though, now that I've seen them I kind of get it, they're cut close to the body (esp through the lower leg) but not as close as a typical skinny
