Hi Ozzie
If you've been reading the posts, you've probably learned that NH has the higher property taxes, which is offset by the fact that we have no income tax, no sales tax, and car insurance *can* be much more reasonable than in MA (shop around!!)
School rankings can range considerably, the higher taxed towns also tend to have the best results in overall test results (no surprise there...)
I think most would agree that Londonderry has one of the best school districts in this area. Their HS band travels all over to perform (NYC parades, Disney, Rose Bowl parade, NASCAR, etc) and these trips are NOT subsidized by the town taxes.
Nashua has 6 or 7 elementary schools, 4 or 5 middle schools and 2 high schools. I don't have specifics on which are considered "best"; maybe someone on the board has personal experience with Nashua schools?
Bedford just broke off from Manchester and has its own new High School (they used to go to Manchester West). I've always heard good things on their elementary and middle schools, particularly Mckelvie and Peter Woodbury schools.
Windham has a good rep, but may be having some growing pains with the High School that they are just opening as well (formerly went to Salem High)
Other towns to consider may be Hudson (with a tech/agricultural HS), Hollis or Merrimack. Apart from all the great answers you'll get from the people on this board, there is a great resource on NH school demographics, performance, and so much more at this link:
NH School District Profile
Please feel free to ask any questions on schools, towns, etc and I'll try to help if I can...