[villagetinker]

I agree you will get plenty of comments on installing gutters, but here is one you really need to consider.
Right now the water off the roof tends to be dispersed, with the exceptions of the valleys. When you install gutters you concentrate all of the water to the downspouts, so be real careful where and how the downspouts are located, or you may end up with real problems.
We installed gutters at the front of the house due to staining on the driveway, and around the lanai in the back. had to significantly change the drainage of the downspouts with the new landscaping to avoid having a lake in the back yard.

Hope this helps.