The Kelly Clarkson and Clay Aiken concert

The Kelly Clarkson/Clay Aiken concert Monday night at the United Center was exactly what you would expect from a pair of winners — well, one winner and a runner-up — from “American Idol.” It was sweet, earnest and well rehearsed, but not particularly memorable. While it’s clear that each performer has a strong set of pipes, neither has toured enough to put on a truly exhilarating live show. You can sit home and listen to their CDs and pretty much get the same experience.