I keep meaning to watch "About Schmidt" too. I haven't because I understand it's pretty much an introspective film and kind of slow going. Seems like my tastes are kind of seasonal, and I'm not in the mood for it right now. But one of these times, I'll check it out for sure.
I'll tell you a relatively recent Nicholson film I liked. "As Good As It Gets" is a movie where Nicholson plays a rather cynical curmudgeon with a bit of heart that he desperately tries to keep hidden under wraps. But it shows anyway, just through the cracks, just enough that you can tell. It's a part that I think was made for Nicholson.
Another recent film that I thought was worth seeing was "Something's Gotta Give." Another made-for-Nicholson film, in this one, he's an aging Playboy that's always gone for younger women. When he meets the mother of his latest girlfriend (Diane Keaton), everything changes.