My favourite Chinese films are probably Wang Kar-Wei's 2046 and (amazingly) Zhang Yimou's 我的父亲母亲 (translated title: The Road Home). The first is available in a mandarin dub. The second doesn't have much dialogue, but it's a fantastic tear-jerker that is beautifully filmed. Hard to believe it's the same Zhang Yimou who has gone on to produce such bad films as Curse, etc. The Road Home is also Zhang Ziyi's first film btw.

For more fun/casual films, I really like the older Andy Lau comedies from the first half of the decade. 老鼠爱上猫 is a fun romantic comedy (with a really cute Cecilia Cheung). There is also Missing You, an office romance. All these are Cantonese films, but any Chinese language version should have the mandarin dub availablfe.