I'm thinking about my next investment being a better external flash. I'm looking to get into some portrait photography, but I will be doing plenty of other stuff as well. I've read some of the differences around, but I'm trying to determine if I should get the 430 for now, or just go for it and get the 580. I was thinking go with the 580 because then I've got the power, and if I want, I could get another flash as a slave. But then again, I thought I could get the 430, and if I need more power, then I could get the 580, then I can use the 430 as the slave. Any ideas?