What size board should I get?!

I am 6'1" and 160 lbs. The only time I have surfed was about 2 years ago, for a few weeks in christchurch, new zealand, back when I was a couple inches shorter and a few pounds lighter. Obviously I started out on a longer 8 foot foamy, but I worked my way down to a hard top that was probably about 7 feet long or so. I didn't have much troubles with it, so I'm wondering how big of a board I should get, I'm in really good shape and hoping to get a short board, it'll be mainly for New Zealand so not the biggest of waves but it's got quite the range. Any advice?