if you are more into people and less into beaches, go to HKG. I'd do two days HK and one day Macau.

NT can be interesting if you can get your way into some of the little villages (what's remaining) and see the people and old houses.

If you like walking... Day 1 Do causeway bay to western (check out Man Wa Lane and western market).

The next day take the ferry from Wanchai to TST and walk up to Mongkok on Nathan Rd and check out the street market on Tung Choi St to test your negotiation (haggling) skills. You can also do Temple Street market.

For some reason, I always feel a big contrast btw HK Island and Kowloon. I'm very partial to HK Island.

If you want to try out local laymen food, you will see plenty along the way.

have fun.