Exchange Server 2003 – Maintenance and Reccovery

I am searching for the best and/or fastest disaster recovery methodoloy for my exchange server. I have one 2003 Exchange Server Enterprise Edition running inside Windows 2003 Server Standard Edition.

Currently the server needs Windows SP1 and Exchange SP2 to bring it up to date. I understand people who have Exchange 2003 Standard will benefit the most from SP2. I am really leary about doing anything to the exchange box because exchange seems to be very sensitive about configuration changes. Should I install SP1 or SP2 on exchange?