We are traveling to Hawaii the last two weeks of July. All of my friends and family have expressed concern for us with this whole North Korea thing. Do we really have that much to worry about? Would you still go?

My suggestion is to check the International Travel section of the U.S. Department of State website.

Yes I would go--it wouldn't occur to me not to! Our office does quite a bit of business with Hawaii and I have coworkers going frequently, and no one has even brought this up. If there is real concern the state department would put out a travel advisory.

We're on Maui right now, quite lovely.

They did move some sort of anti-missile/radar device out from Pearl Harbor into the open waters off Waikiki last week but I didn't pay too much attention to it nor have I even watched the news.

Interesting that you should ask that.
We have been living on Maui since February, and have yet to hear or see any local concerns about it, or even public announcements.
Actually, national news yesterday declared that North Korea does not have a missile that can reach Hawaii yet.
Also no advisories(as far as I know) have been listed against visiting Hawaii.
I would say, come and soak up the sun

Gates Orders Missile Interceptors To Hawaii

The supposed missile would target Hawaii around July 4th, Independence Day. They doubt that any missile would reach U.S. territory though.

Headline in today's Maui News, "Long-range missile not threatened by N. Korea...If US intelligence accurate, Hawaii is in clear for now." The story also appeared yesterday in the Honolulu Advertiser