Canon Rebel T3 - Canon Speedlite 430EX II or 580EX II ?

I own a Canon T3 and I started to build up my gears. Currently I only have 3 lenses: [1] Pancake F1.8 50mm, [2] 18-55mm f/3.5-5.6 (comes with the bundle) and [3] 200mm F4.0.

I usually use this camera for event shooting and on wedding day (my focus is on the bridal side). Since most of the time, I took indoor shots and people are moving around so I often use burst mode to capture a couple shots to pick out the best one.

So should I get the 430EX or 580EX?  I want to get only one time and not switching around.

Thanks in advance for those who response.