I would suggest up to 5 days in Hong Kong. As for what to combine it with- it depends on what of sort of thing you want from your holiday. When we went to Hong Kong we combined it with Bangkok( and Koh Samui for relaxation.) BKK is very different from Hong Kong. We are going again this Easter and flying on to Saigon and then Bangkok.
I'm sure others will have ideas.
If you want city break plus relaxation - try Bangkok and combine it with Hua Hin or Phuket or Koh Samui( HH does not need a flight)
Are you tied to a maximum of 10 days?

I've just started to look at combining a week in Hong Kong with a week on Hainan Island in China for next year. It's only an hour's flight between the two and Hainan got a good write up in one of the weekend travel supplements recently for the relaxing part of a holiday.

We've previously combined HK with Langkawi, Singapore, Bangkok and Bali (as well as just going to HK on its own!) and I'd definitely recommend planning a few days' relaxation time into your trip. There's loads to do in HK to easily fill 5 days, but it can be very tiring and you'll appreciate a few days on a beach after all the sightseeing.

If you want some ideas of what to do in HK, have a look at the report I wrote here about our trip there in Dec 2004/Jan 2005.

dont get me started on Singapore and Bali!! If you can combine with Bali you will love it I'm sure!

Hi

I totally agree with the advice you have been given Hong Kong is great for a stop over but I would hate to have stayed more than a few days. I was working during the week in china and stayed in Hong Kong 2 weekends Fridays to Mondays and I have to say I had defo had enough by the time I was coming away. Theres only so much shopping you can do and I can shop with the best of them, the heat and smog really gets to you after a while. But the city is well worth it on a whole simply to take in the view of the Sky Line......