I'm a little late to the peplum party but I'm starting to understand the appeal (see here and here). It's the shape, or the illusion of such, that makes it universally flattering. Whether you're built stick straight or curvy, you want to emphasis your waist line, as it's the narrowest part of you. This top hits me at my natural waist and flares out. While it does accentuate my hips, which are most definitely not narrow in any sense of the word, the belt further cinches in and creates that hourglass illusion.
Purse: J. Crew Factory
Belt: South Mood Under
Shoes: J. Crew
Jewels: J. Crew, F21
Lipstick: Guerlain Rouge Automatique in 121