Aug 11-14 and Aug 22-24 are official holidays in Shenzhen due to the Universiade [source] 

Update July 2011: Universiade holidays declared 

Update August 2011:  My employer (Tencent) only gives 1 day off (Friday 12th of August) and the other days are just normal working days. I've marked these days with ***

Especially the Mid-Autumn festival dates are always hard to predict. It should be 8 days total.

Updated 28th January 2010: The Spring Festival holidays will last from Feb. 13 to 19. The following Saturday and Sunday (Feb. 20 and 21) will be working days.

Updated 29th July 2010: The official schedule for Mid-Autumn and National Day holidays has been added. Many people are unhappy about the schedule! 

The official public holidays in 2009 (year of the Ox) for China are confirmed, this is the final overview:

Notes : the National Day holiday and Mid Autumn festival in 2009 are very close together. Confirmed: they will be combined in a long holiday (8 days) starting October 1st. Previously this table stated the holiday will probably start September 26th, but that was wrong.

* About the May 1st Golden Week in some provinces: IT HAS BEEN BANNED BY THE CENTRAL GOVERNMENT:

"In a surprise move, the State Council banned any special holiday arrangement Thursday, the day after Guangdong had made its golden week national holiday announcement" (source). Article about the original plans for the May 1st holiday: source 

To summarize, the two golden weeks in 2009 are:

• January 25 - January 31 (7 days)
• October 1 - October 8 (8 days)

The total number of vacation days in China in 2009 is 15(+2) (excluding weekends of course).

source Chinese holidays (Chinese)

The official public holidays in 2008 for China are:

August 8 has been proposed as a national holiday called 'Sports Day' but has not been approved as of April 2008. The current status is unknown. The parts of the calender marked in red are the two 'big' holidays in China during which most Chinese can travel.