Very late, but might help someone else's checklist... here some gear turned out to be more useful than I expected, some didn't.
I had a rotation of toothbrushes for my daypack, as well as one for the hotel room. But why bother when you can't use tap water? In hindsight I would have brought more solid toothpicks and gum.
A bandana turned out to be vital. I had a 22-inch red cotton paisley bandana, just $2.99 from Kaplan's on Market St, and used it everyday for drying hands at the washroom, acting as a bib when slurping oily noodles, and only after that for emergency warmth. Turned out to be much more useful than in San Francisco.
If you need an alarm clock, you'd better bring it... out of seven hotels I stayed at, only one had a clock, and it was an Australian chain. Wake-up calls might be reliable at the larger international hotels. I think only two of those hotels had fullsized telephone books, and I never did quite figure out how the book was organized.
I wish I had done suitcase size better. I wanted to travel light, with just a carry-on and a daybag, but a regular check-in-sized bag would have been easier. I brought a few too many smaller packing bags, and sent some back when leaving Beijing, but I stayed with nearly two dozen small packing organizers, in my hotel bag and on my person.
A variety of locks for different bags proved vital. A retractable cable lock could secure the suitcase. A PacSafe Hip Pack was brilliant as a tough comfortable fannypack which could be locked shut underneat the bed frame or to a desk leg.
I never used a transistor radio, but wish I had. Listening to local radio can add a lot while walking around. I think the sidewalk situation in China was too demanding to make it comfortable though.
Paper napkins, folded into quarters, added to a pocket at every meal... much easier than carrying around a pack of paper towels. Had a half-ounce container of alcohol-based hand-sanitizer in a plastic bag in my vest pocket, used whenever I touched a handrail or other public surface. (I had remarkably few respiratory/viral symptoms this trip.)
Aerosol saline was a surprise hit. If the air is dirty or dry, and you can't rinse your nostrils with tap water, a half-ounce bottle of nasal spray not only helped cleaning, but helped prevent chapping or damage. And Chapstick or other lip wax always comes in handy for protecting small skin tears from the environment, lubricating friction points.
I used a lot of the Aerborne style of carbonated Vitamin C tab. I wish I had brought more. I'd often drop one in a plastic bottle of tea, while walking around. I used just over a bottle a week, and could have done two.
I didn't bring gloves, but wish I had. Not for the cold, but for the public stairways, door handles, subway straps, and other contact surfaces.
Sunglasses seemed an essential for me, but in Beijing the only others wearing them were police. In Shanghai I didn't look quite as strange.
Clothes layering worked, but could have been better. I had a few medium-weight durable cotton buttondown shirts, which actually served as my warmth layer, rolling up sleeves and unbuttoning when needed. My Filson Travel Vest was my base layer, the one I never took off... I almost went with a ScottEVest, but the Filson pockets hold paper better, and the material and construction have less risk of failure. Base layer was a synthetic longsleeve athletic T, or two of them when it was cold... REI, UnderArmour, fast-washing shirts. I carried a silk-weight synthetic pullover shell as a windbreaker, added beneath the vest, for emergencies. On one of the early nights I was surprised and chilled, but otherwise this layering handled the temperature and comfort ranges remarkably well. (I had planned to get a light sportscoat there, as an overlayer, but the hard sales pitches made it very difficult for me to feel comfortable buying anything. The prices I saw were not, I knew, the prices I was expected to pay, and I just had no stomach for it.)
Power converters worked, even though I didn't know what I was doing. I had trouble finding the right kind of gear for awhile, but Radio Shack stuff was easy-to-find and worked great. Some of the adapters I brought I did not use, but actual wall outlets did not always match what the internet said I would see. I should have brought an extra splitter cord so that I could charge camera and computer simultaneously. One unanticipated problem: The wall outlets are frequently rickety and in strange places... a better way to prop up the converter in the socket was a frequent issue.
I didn't bring my own electric kettle, but these hotel-room fixtures were a constant ritual... boil a pot of water whenever I could, pour it into empty orange-juice bottles when cool and keep in the fridge. Long-term drinkers of municipal water may need to worry about pollutants, but us short-term users are more concerned about the bacteria. The electric kettle was a part of each day's routine.
It's probably not for everyone, but I'd recommend a walking cane if travelling, particularly in crowded cities of uncertain footing. Even without injury it can reduce the strain of long days on your feet. Holding it at your side can help in defining personal space... trailing it behind you while waiting in line deters the eager from bumping up into you. I've used it as a seat too. Carrying a light hook cane was never a burden for me on this trip.
Maps were difficult. In San Francisco I bought every map I could find, and brought all that had some unique angle. But all were out-of-date, and it was difficult to find things. Even mapping the surroundings to the paper was typically more difficult on this trip than usual. Some hotel tourist maps turned out to be my main maps. Internet mapping was not practical, in China, on a Nokia N800 pocket computer. Overall, it always took me a few more days than normal for me to feel confident I could predict distances and efforts. If going back, I'd put more work into my map preparations.
With guidebooks I had a similar approach, but only took two per city, with some razored-out pages from other books. In Shanghai I added a few pocketbooks, and usually carried three guidebooks and two maps. That was too much, but not enough! I'm not sure how to improve this, unless it's to memorize material from lots of books before leaving.... :(
Phrasebooks didn't matter as much. I'd usually have an emergency phrasebook in a back pocket. I rarely used a dictionary.
And for a hat, just a simple red ballcap of cotton twill worked day in, day out.