Microsoft Outlook is a great email client and personal scheduler, but it can be a resource hog. Instead of keeping it open all the time, you might consider using the Mini Outlook Inbox (and More) gadget. It gives you a quick and simple view of your email messages, appointments, and tasks.
Click on a message and it quickly loads directly from the gadget, no waiting for Outlook to open. You can hit Reply, Reply to All, or Forward, and a new message will open from the official Outlook. Button on the gadget let you quickly start a new message, select or open folders, and send/receive.