Differences between 220ex and bigger canon flashes..?

[OverRunWithSons]

I just bought an Rebel XT, did not receive yet and now in search for external flash. I am new to Digital SLR's and very very confused by manually doing anything at all with a external flash system-plus they look so huge, I doubt I need the extra distance in lighting. Most of my pcitures would be for Portraits , indoor situations with kids, landscapes in daylight. Sports action , night time stuff is never something I cared to take pcitues off. I guess my question is: When would I accually need something bigger than a Canon 220ex speedlight?

[SkipD]

You'd definitely need something bigger, in my opinion. The 420EX isn't too bad (I own and use one), but what you are describing yells 580EX to me. The added power and ability to put the strobe into manual mode are two significant advantages. The only down-side that I see to the 580EX, as compared to the 420EX, is size. It is a bit bigger and heavier. Performance is what really counts in my book, though.

[OverRunWithSons]

I think i am fully convinced that I need at least the 420Ex , since I am spending so much on the XT, why get a wimpy flash with no bounce capabilities. I would even consider the 430ex, can anyone tell me the real differences between the 2 besides $100 cost ?? How much smaller is the 430ex compared to the 420ex?