Accessories for My Impulse Buy Flash..Help!

[expatdude]

Ok, so I'm finally going to get a flash, 2 years after starting this photography hobby.

I will get the speedlite 580 for my 40D (and the wife's 450D), and just want to know if there is anything else I need to pick up at the same time (batteries?). I know I should have done more research--spank me. It's a bit of an impulse buy.

Thanks in advance for any good advice, and I forgive everyone who decides to lay into me for my laziness in not doing the legwork I should have.

[Anke]

Batteries will be required of course, and some good rechargeables are your best bet. Do a search here on POTN for the most recommended but in my searching experience I found Sanyo Eneloops are the most popular. That's what I bought.
Read up on the right output and lifetime of charge too (it'll make sense when you search ;)).

[Curtis N]

NiMH Rechargeable batteries - two sets and a charger.

Avoid the store-bought diffusion devices for now. Practice with the built-in catchlight card and perhaps an index card held on with a rubber band.

Practice learning about light. http://strobist.com is a great place to start.