Just sent out my May newsletter. As much trouble as it is, I have found that clients truly enjoy getting the newsletter. I send it out to almost 400 people on a monthly basis and about 85% get opened every month. It is so much easier than traditional mailing and it is great exposure as often it will be forwarded to a friend.
If you don't do a newsletter, I strongly encourage you to look into it. It is a tremendous marketing tool that only requires a few hours a month.
Tell me about your newsletter, we can share ideas and maybe get some good new ones in the process.