Activity for blessed

I always hear you need a theme for your wedding. well.... I can't think of anything AT ALL!! do you have to have a theme? and if so what would be some good themes? I know i don't want anything crazy or immature.

My wedding isn't until august 2009, but its all i can think about right now. I feel like it's to soon to be planning. what is a good time to really start investing time into the ends and outs of a wedding?