What altitude were those wind readings taken from? Most nation servey are for 50m in hieght. If those are from your own wind speed sensor, what height did you run it at? If say you placed it on a pole off your roof at say 30' and you are running a HAWT at 60' then you are looking at a bit more wind. If these are readings from 150' and you are running at 60' then your wind speed will be much lower.
That said I would likely go with a standard Hughs Piggott style (likely spelled really bad). Something in the range of 12-15 foot would likely do you well. Here are some great pages on building these...
http://otherpower.com/17page1.html
http://otherpower.com/new17page1.shtml
This second one is a second 17' that they made and includes some improvements. One thing you really need to be carefull of is reliability. Make it tough, do good welds, protect everything from rust, use tread lock and lock washers, and use very strong bearings (and grease the snott out of them). The blades should be coated with a marine grade sealer or epoxy coating. The tower needs to be very strong with lots of support wires. A tip tower would be nice incase you have a huricane coming in or you need repares.
Now you need to keep a few other things in mind... It sounds like your tower is going to be a long ways from your house. The power from the stator is A/C and is run through bridge rectifiers or diodes to make it DC. DC does not travel long distances well. It would be best to convert directly to 110v A/C. Make a little shed at the tower base with you breakers, load dump, fuses, and invertor (and battery if you are looking at a power back-up or off grid set-up). Also realize that an on-grid or grid tied invertor is VERY expensive. I have been looking around and even for a 2Kw you are looking at about $2000 or more. Also even at AC you might get voltage drop running to the house. you might need a transformer at the house to get a full 110v. Also the cabling might be pretty expensive if you are running a few hundred yards to the house.
