I'm looking for a camera that will take care of my kids birthday parties in both jpg and mpg formats that will also take good macro reef shots.

Can any of the cameras out there auto focus on a coral in a macro shot?

I've been using a Canon PowerShot S40 and I love it's features but here's one of my problems:

In an auditorium, 50 feet away from the subject, I can't get a good shot. If I use flash, for foreground lights up only. With no flash, I need a long shutter and everything is blurry.

This camera has a small lens. Will cameras with larger lenses like the SLR cameras capture more light and use a shorter shutter?

Jack