Yes, The Tree is ok, and also maybe next wednesday you might like to try Le Cafe igosso, they have some live jazz starting around 8, and that really is a nice place, they have the best selection of drinks in Beijing, I mean you can find almost anything from anywhere, and it's never too crowded, but never empty, nice cozy, cool atmosphere.

It's on Dongsanhuan Nanlu, about 500 meters south of Guo Mao bridge, on the left hand side if you're going from Guo Mao, first there is this japanese restaurant called something like Haishiya Meishiba, and then there it is, Le Cafe Igosso.
They also have a restaurant (italian), but it's very small, and very stylish, so there are like two parts of that place, a cafe, and a restaurant behind that. It's great. The band is very good, the singer very cute and has a great voice (much better singing then at The Centro, I would say). Really great place, you should check it out, but I think this live jazz music thing is only on wedensdays. Enjoy

Hehe what does an American look like? lol j/k

Cheers