I loved Eats, Shoots and Leaves, too, but must say my all-time favorite is Woe Is I by Patricia O'Connor. The way O'Connor uses humor to teach the lessons--you'll never forget the rules again! And don't laugh, but I found two children's books invaluable--Grammar Smart Junior by Liz Buffa, and Punctuation Power by Marvin Terban.
Even as a kid, I've always needed a lot of solitude, so the writing life is a perfect fit. Personally, the best time to write is very early morning, before the world gets a chance to sink its teeth in me.