Stimpy,
The Novotel les Halles is indeed near the Châtelet Station exit, basically you get out of the station through the Porte Berger exit (3 flights of stairs, all with escalators), and the Novotel is just here to your right. It's true that for your purpose it is quite convenient. The neighborhood is a bit rambuctious but quite colorful.
Drop by the Banana Café for a drink...