Just read the article, "Making your garden a home for beneficial insects," in Acres magazine, Vol 39, No. 10, and it is a great resource. It says that more than 90% of insects aren't pests, and talks about getting on the same team with them. There are three kinds you want to attract: predators, parasitoids, and pollinators, and the trick is that you need a certain threshold number of "bad bugs" in order to attract the "good bugs" and get them to hang around. This means being willing to have "a few lacy leaves." The article also has charts of pests and their corresponding predator insects, as well as plants that attract beneficial insects. Good stuff.