New Zealand - Air Travel Agency?

Looking for a travel agency that can help me book airfare to New Zealand. Too many possibilities for me to deal with a few wrinkles I'd throw in to complicate things like a stopover and upgrading with miles. I think I could do better than my usual agency which does ok with run of the mill 'here's the package' kind of deal. Don't mind paying for good service. Anyone ever had experience with such an outfit? How do I find them and how do I know they're good? Forget a google search - it just turns up lots and lots and lots but again, I think the only way to know if they know what they're doing is if someone has used them. Thanks.