Best travel guide books to Hong Kong and Beijing?

I am travelling from Connecticut to visit Beijing and Hong Kong! I've never been to Asia before. I'm 25 years old and am thus interested in a lot of young person things like good dining and exciting nightlife. I also want a well-informed and intellectual account of the cities' culture and history. Any suggestions on the best books? Lonely Planet? Rough Guides? Time Out?

I always use Frommer's books...