To add to the Zhongguo Tong/language expert, the guys who insist on speaking in Erhua-yin ALL the damn time, even when they aren't in Beijing and it is completely inappropriate. His close cousin is the asshole who speaks to other foreigners in Chinese. All the time. He has also been known to introduce himself to other foreigners using his Chinese name, which is usually something douchey. Met a guy the other day whose Chinese name was "shuai ge." You're awesome dude, really.
The guy who is just here for the girls. Remarks often and loudly about how Chinese women are so much more __________ (insert favorite trait here) than Western women. Fetishizes Chinese women and lumps them all together making remarks like "Chinese women really know how to take care of a man." They also tend to have an irrational hatred for Chinese men and will make remarks about penis size and how Chinese women never go back to Chinese men after they've had a "real man." Often has a Chinese girlfriend who he can't communicate with. Extra points if he met her in a KTV or a disco.
The "Orientalist." Wears Chinese cut suits and has a house full of crappy scroll paintings. Is learning Chinese calligraphy, the erhu and Tai-qi. Probably lives in a courtyard house, or wishes he/she could. Considers himself a Buddhist and makes offerings at the temple. Has fully embraced Chinese traditional medicine, gets accupuncture and medicinal massages and has even gone in for cupping a few time. It is important to note that any one of these things on its own is not irritating, it is embracing everything traditionally Chinese or "exotic" that crosses the line into objectification. Funny you never see these guys into long pinky nails or state controlled media or big stupid hairbows or struggle sessions, huh?