What to bring vs. what to buy in beijing?

Do not bring anything that ends in a plug unless you have a 110 - 220V transformer.

You can get almost everything you want in Beijing but, without being rude, your figure might not be compatible with what is in the shops.

Ladies sanitary products might not be the same brand.
Shaving cream limited selection.
Deodorants limited selection.
English books will be cheaper in the US (there are though a couple of libraries).
and before you arrive install in your computer a VPN/tunnel/proxy.
Bringing anything valuable then get insured via you current home insurance policy - insurance is weak in China.

Linens, towels etc of course are available in Beijing but quality might not be the same as you would expect.

Thanks for the reply - this is very helpful!

A couple of other things to think about bringing:
1) good map of Beijing in English
2) cell phone with gps that is not locked to a carrier (iphones are available in china but lack wifi right now) or a gps with maps of Beijing
3) Coffee if you can - its pricey here
4) Printer for printing directions which you can give to taxi drivers - if you are not going to have a car.  You can buy one down here but if you have one it doesn't hurt to bring it

Cell phone - yes make sure your phone is not locked. You will doubtlessly want to get a local number instead of using your US number. If it is very basic phone make sure that it can display Chinese characters so that colleagues/friends/pa/or how to get there services can send you the address in Chinese. If your phone is in the Android/Blackberry/iPhone league that should not be a problem.

Printer, if it needs a plug you will need a transformer or at least make sure it can be used on 220V.

Try buying the Yunnan coffee instead of bringing across tons of coffee from the US - it's not bad.

Map nice idea, but with the pace of change in Beijing make sure it is the latest version. One can of course always use Gooogle Maps but sometimes it is not accurate.