This is why Cascada doesn't quite fit the example, it's just the one I think of most obviously as doing something boshy. Scooter seems to be the Center of All Bosh in my own mind, though.

Ke$ha's tone of voice, whether she's singing nonsense or not, often seems of the "neener-neener" variety, snotty and petulant (I even find this to be true in the more Katy Perry-like ballad songs, her singing voice having a certain throaty screaming quality to it), whereas Gaga actually makes even her gibberish signify somewhat...well, maybe "tastefully" isn't the word after all. But there's something cool about Gaga that Ke$ha doesn't have.