Paihia's the place for New Years partying. Lots of backpackers there, couple of good bars.

Kerikeri's OK.

If I'm going near KK on Sundays I stop in at the Farmers Market. Nice atmosphere and good food.

The town itself's a bit trendy for me, but wife loves it. Goes down there with her friends for expensive coffees & meals.
Sister lives there & also thinks it's a great place.

I head out of town to Manginangina Reserve at the Pukete Forest.
There's a boardwalk through the Kauri forest there. Nice place to spend an hour or two.

The Stone Store & Mission station's an old favourite relaxing spot. Nor far from the town centre.
Mellower since they removed the road bridge & stopped the cars coming through.

Couple of friends camped at Aroha Island last year. Went Kayaking, loved it.

What happened to staying in the DOC campgrounds further North?
Sleep in your car if you're worried about Psycho killers:)

Getting a bit late now for hostels etc. as things are busy for the summer hols.
We have a small backpacker's hostel on the East Coast, it's already fully booked well into January.