A post worth reading (and you should take the survey too) on bizCult (hat tip to China Law Blog) about how the Chinese hills aren't exactly paved with gold. According to the blog, "the majority are 26-30 year old professionals from North America making US$10,000-$19,000 a year." I'm not surprised about the age group, but I'm highly surprised by the salary, though part of the problem might be the small sample size so far.
The problem is, the blog makes a MASSIVE assumption: that most expats in China can speak at least decent Chinese. This is also a big problem with the survey, as it doesn't inquire about the respondents Chinese fluency. Many expats are here teaching English who can't speak a lick of Chinese, and this probably accounts for a number of the lower salaries. I'm only taking a wild guess, but I believe that if you look at salaries of those who are fluent or have a high level of fluency to those who can't speak any (or very little) Chinese, the numbers would be fairly different. The survey also may be skewed because a lot of white collar expats who are making the big bucks work for bigtime foreign companies with very strict firewalls.
Chinese salaries for expats aren't as high as people think. Above the Law's Asian Chronicles recently mentioned that salaries in Biglaw on mainland China, which used to range from $35,00-60,000 a year now can go as low as $15,000. On purely anecdotal evidence, and I'm not one with a lot of expat friends, I would say that most 25-35 year old expats in professional jobs are making between RMB15,000-40,000/month (this is solely in Beijing and Shanghai). In these cities, I'd argue its hard to live comfortably, go out sometimes, and save a little on anything less than RMB15,000/month.
If you're an expat and you come to China looking for a job, you better have 2 out of the 3: a unique specialization, an idea, or excellent Chinese skills. As pointed out by bizCult, Chinese are speaking better English than before (and obviously speak better Chinese than you), are spending more times overseas than ever before, and are willing to work for less. That said, there are more foreigners taking jobs with Chinese companies (as pointed out by CLB), especially as Chinese companies take over more and more foreign ones, and Chinese companies are offering better wages than in the past (while maintaining their traditionally strong job security).
Just some random thoughts on a late afternoon in Beijing.