Good suggestions - I'd also add shots of the HK city skyline from Kowloon side, near the cultural centre or Star Ferry, and perhaps a trip up Stubbs Road (before you get to the Adventist hospital) for interesting high-viewpoint shots of the Happy Valley racecourse and a slightly different angle on the city skyline.
There's a new cable car you can take up to Big Buddha at Po Lin on Lantau Island, and on a clear day the views can be excellent. Cable car views again from within Ocean Park (dreadful place, but lovely cable car views).
Hiking in Lantau (where I live) can give rewarding seascapes with HK Island in the distance, with some of the smaller islands (Peng Chau, Cheung Chau, Lamma, Green Island) leading up to it. There's a nice easy walk from Discovery Bay to Mui Wo (Silvermine Bay) which will reward you with great views on the right day.
All of this supposes though that the visibility will permit this. We're coming into Spring here and the haze is a bugger. If the visibility is poor, there's always the classic HK shots of the neon in Nathan Road. Perhaps also try Man Mo temple in Hollywood Road; Ladder Street; the markets in and around Peel Street / Wellington Road, Central. And of course the sights of Lockhart Road, Wanchai at night
