I know that people often wonder what the best accessory is for their new DSLR. I struggled with this too... Many often forgo the flash, putting it off until after buying lots of others things like several lenses. I've found that the flash is probably one of the most useful accessories... I should say *the most useful accessory* you can buy. It's not just for shooting in low light, it's also very useful for shooting in extremely bright light as well. I was on vacation last week visiting family. I went to the park in Kansas with my son to get some pics of his first time on a swing. I brought my 5D and a couple of lenses plus my 580EXII Speedlite. ...a Speetlight on a bright sunny day? There should be plenty of light, right? Sure! But there's also plenty of harsh shadows to go with it. Here's an example of a shot taken without a flash. Not bad, right? I don't think so. My son has the most beautiful blue eyes, but you can't see them in this shot. The sky was cloudless, the sun was directly over head (1pm) and there wasn't any shade available (trees or the like). So I mounted the Speedlite to fix things. I dialed the flash back to -1 stop and shot. Here's the result. In my opinion, this is much better. Now you can see his eyes and there's better separation between him and the background. I didn't bring my defuser, which I could kick myself for, which would soften the light a little more. But still, the effect in my opinion is much better than not having used the flash. Just thought I would share this with those who might be thinking about what accessory to buy next.