Originally Posted by ddt0725
You'll be very happy with the 580EX II. It's very flexible, the extra power is worthwhile, you can trigger 430s (and 580s) with it, and you can add an external battery pack for speed and convenience.
As far as the Sto-Fen, I have two, and they NEVER get used. Some people like them, I just have never found them to be good at modifying light for me. I use a combination of umbrellas and Rosco 103 Tough Frost gels to soften and spread light. But, your mileage may vary.