Fiji or Tonga?

Hey, I'm currently in New Zealand and hoping to go on a trip in late December for ~3 weeks. I either want to go to Fiji or Tonga... what would you recommend? I don't really want to stay in a tourist resort, rather go somewhere with culture etc, and just to relax/surf, and also not spend heaps of money. Any suggestions? Cheers!

In Fiji for somewhere with culture, relax/surf and not spend heaps of money

why not try a village homestay. Lots of culture and very inexpensive and great fun.

http://www.fijihomestays.com/index.htm

hope this helps

Fiji is also the one easier to get around by sea - this could matter if you want to visit outer islands and are on a budget.
It also has (much) bigger islands than Tonga, which makes it easier to get off the beaten track even if you just stay on the main island of Viti Levu.
Tonga is probably the more traditional one though.

Fiji is a bit more diverse, and cheaper to get around. Tonga would be good, but a lot of places fill up early for Christmas, as do most internal flights to Ha'apai and Vavau.