Xiaojie,
Depends where you're moving from and what sort of journalism you'd be engaging in -- just like it any other profession I'd assume.
I know SCMP and some of the local TV channels pay their journos with peanuts. The big name US newspapers overpay their reporters (don't think I'd call them journalists) and put them up in expensive expat housing -- atleast this was the case aroudn '97.
If you can pick a number, pick a high number...
We've got some living costs worked out on the forums. Take a look here ..
Cost of living in Hong Kong
Rent is usually a big part of your salary and the first year's tax is about 30% (one year back tax and one years in advance) of your salary if you've picked a high number.