I will be photographing an outdoor ceremony during the late evening/early night times. I'm beyond excited and welcome the challenge. Speaking of which, I am currently using a very trusty 20d along with EF 50mm 1:1.8 II and EF 28-105mm 1:3.5-4.5. I will have an external flash w/ diffuser (which I prefer not to use too much or at all, just my personal preference) and a tripod in case of extreme low lighting conditions.
In the highly event that I will not be able to upgrade to a 50d before the event (for a much higher ISO options and better fps), I will be somewhat restricted with 20Ds ISO capabilities. Any suggestions?