Nah, Katy Perry's all right! Some totally vapid songs, but she tends to put her name to some of the better dancey pop stuff.
I seem to remember Jem Godfrey (who does this for a job!) singing the praises of Toxic, by Britney Spears, a little while ago. A lot of these songs are produced in ways that don't particularly tickle me, where I don't much care for the layers upon layers of bubble gum, but there's generally a lot of thought and theory put into them by the songwriters. Hit-writing's fierce. There's this little thing in the bridge, for Toxic, where it goes, "oooo-oo-Weee, oooo-WEEE," and it's actually the main "WEEEE-oooo, Weee-oo-oooo," backwards. It's a really neat detail, and I'd never have noticed if Jem hadn't pointed it out.