The best way to improve Outlook's performance is to not use it. And unless you're way out in the boonies where it isn't available, a DSL line only runs about $30/mo.*
I started using web-based e-mail a number of years ago, when I was between computers. One thing I find web-mail has over Outllok is that nothing is stored directly to your HD unless you download it yourself. All mail, saved mail, address book(s) - it's all stored on the server.
I once had a major system crash because the HD went south. After fixing the problem and re-installing the OS and other software, everything related to e-mail was still right where I'd left it- on the server. Nothing lost. And with nothing being stored directly to your HD, security becomes an order of magnitude higher. Best of all, you can have multiple web-based e-mail accounts. Give the authorities access to your every day account, while the nefarious activity account remains hidden - in plain view, so to speak.
* New Hampshire - other localities my vary.
Edited by MattV, 01 December 2007 - 12:18 AM.