Tin Hau is a very convenient place.
From Tin Hau to HK station (in Central), taxi ride takes about 10 min (~ HKD 35)
Then you can check-in for your flight at the HK station (90min before your flight) and take the airport express right there straight to the airport !
There is discount for airport express ticket from 15 Dec 2007- 14 Dec 2008 !
http://www.mtr.com.hk/eng/airport_express/promotions_4persons.html
