Lived in Sydney for nearly 12 years but still regard myself as a Wellingtonian - get back quite often and have taken a few pics - incl. a (very) few on my site at
http://www.uber.com/phil - I'll actually be there on the Thursday and Friday (but prob. tied up for work).
Wellington is a nice 'compact' city pretty much defined by the harbour and the hills with lots of photo opps which can be explored on foot but a lot will be driven by the weather. (Not sure about night photos though - there's some light sculptures on the road out to the airport but not really suitable for walking to or parking).
My recommendations:
1 - the waterfront - from Oriental Bay past Waitangi Park and Te Papa (National Museum) around past the Star Boating Club and the new harbour developments. Along the way there are some quirky sculptures, and poetry about Wellington and a water 'sculpture' by Len Lye.
2 - the Cable Car up to the Botanic Gardens, Bolton Cemetry and old houses on Tinakori Road, the Beehive and old Parliament Buildings (including the General Assembly Library) and the old wooden Government Buildings (now part of Victoria University).
3 - the 'street life' in Cuba St, the former Dominion Museum Buildings (now owned by Massey Unversity) and the War Memorial/Carillion (including the tomb of the unknown soldier).
4 - if you have a car, a trip tbrough Petone to Eastbourne and Days Bay and a trip around the coast from Seatoun (mentioned by Antsl) past the airport all the way to Island Bay. Apart from the rugged landscape there are some 'treasures' like a memorial to Ataturk and an Easter Island-style figure on the coast. There's also a good lookout over the city at the top of Mt Victoria.
5 - time permiting, the Karori Wildlife Sanctuary is world-class -see
http://www.sanctuary.org.nz.
Hope the above gives you some ideas - there's a good Information Centre in the centre of town [in Civic Square]. A lot comes down to what you are interested in (shooting) - nature/old buildings/'street' etc.
Feel free to PM me - would be happy to meet up if I have some free time on the Thursday and Friday!