eaily exchage USD through a bank counter. Just taking your money out, USD or EURO, then went to a bank and the bank staff will exchange that for u.

kayako - What rate is your typical bank offering for USD in cash?

We were in China in 2006 and, at that time, converting American dollars to Yuan in your hotel proved to be the best way to obtain Yuan. The conversion rate was set by the government and was as good as the ATM conversion rate. No additional fees either.

Definitely avoid traveller's cheques!
ATM is the best option. The question of fees is meaningless. Fees are nothing compared to what you lose on exchange rates. If you plan to exchange dollars or whatever to RMB, do it at the airport. The rate is as good as any other place in town and you don't have to waste on hour at the bank.
Use you credit card when you can (hotels and high end restaurants), otherwise China is pretty much a cash society. I have never heard of credit card fraud from other travellers.
ATMs are everywhere. Chinese banks have no fee, only your bank will. Nobody works for nothing. Paying the fee is not bad for the convenience and beat having to carry loads of cash and risking of losing it. Id your bank charges a flat fee then withdraw bigger amounts rather than small amounts every day.