I really liked the first two seasons of House. House was annoying and caustic, but hilarious. I liked him in spite of myself. In the second season, some glaring character flaws in his three staff doctors was a bit troubling, but the show was still entertaining, if a bit predictable. Then came season 3. Season 3 is darker than the seasons before it. From the first few episodes, one could notice that House is being challenged in ways he has never been before. The plot is undeniably thicker and expansive than ever before.
All the greatness in the dialogue, though. House is enjoyable simply for the refreshing dry wit. Yes, the plots are occaisionally stupid, but that's not why its so enjoyable. House is a unique character, and the medical problems are just an excuse for him to say shockingly funny audacious things. If you can live with that, you will love this series. Season 3 is just as good as all the others in my opinion.