The April 2007 issue of Log Homes Illustrated has an interesting article on porches; and there are not only porch photos with the article, but also with the articles on a number of lovely log homes.
The National Association of Home Builders says that more than half of new-home construction includes at least one porch in the house plan. However, some of them aren't being used. You have to plan on how you're going to use it. Do you need to enclose or screen it? How big should it be? The world's longest porch, btw, is the 660-foot-long porch at the Grand Hotel on Mackinac Island in Michigan. If you really want to enjoy your porch, don't make it too narrow. You'll also need to think about the roofline, finishes, and furniture. I like a screened back porch that's big enough for a futon, a big table for meals, with chairs and a few little tables for eating and entertaining.