NZ Is fairly region specific, much like Oz, so no 'one year is great' really, although 2010 and 2013 come very close. And for every poor vintage, there will still be some great wines made, and vice-versa. So generally speaking...
07 very good, particularly excellent for Hawkes Bay Reds.
08 a mixed bag, big crop, whites often below par, reds better.
09 a better, but hotter year, some whites a bit flabby, others are very good indeed. Reds more consistent.
10 was pretty awesome most places, although Waipara was good, not great. Lower quantity means a bit harder to find though.
11 pretty poor overall, but not terrible. The further south, the better is a general rule.
12 Also pretty poor, especially with North Island reds. Central Otago pretty good.
13 Superb most places. Haven't seen too much of the good stuff over here yet though.
This is a good guide...
http://www.winesofnz.com/Vintage.aspxNZ Riesling can be good, typically higher RS that Oz though. And the Hawkes Bay reds (and some from Waiheke and Marlborough) like Syrah, Cab Merlot can be superb, but you have to pick and choose, plus tiny production so not usually 'cheap'.
Depends on your budget as to what to buy.... With 11 and 12 being so poor overall, it's not super easy to find other vintages, but they are certainly around.
Cheers
TiggerK