In the restaurants, hotels etc that I stay in there is no expectation of tips whatsoever. The only time I had the mildly embarrassing situation of a hotel porter "lingering" for a tip was in Hilton Shanghai, don't usually stay in those sort of places
The only time I gave a tip to a taxi driver was a couple of weeks ago when I was struggling to make a PEK-PVG flight and I got the driver to drive uber-fast (and for those of you familiar with Chinese taxis this is really, really fast!!). Made the flight so I gave him an extra 20 kuai.
nickyboy