this is the one that I have and it's got a great zoom on it, which is great for concerts.
Amazon.com: Canon Powershot S2 IS 5MP Digital Camera with 12x Optical Image Stabilized Zoom: Camera & Photo
It's kind of expensive, but for me it was worth the money. It has an amazing zoom. I manage to get decent pictures even being really far back. And it takes video too. Here's some examples:
Took this of Daughtry at an outside concert.. we were towards the back of the crowd. This one's my fave LOL
This of Dane Cook was taken from the upper level:
And here's an example of video.. you can see how far back I was when I zoom in. I was on the lawn.
So yeah, it's not a perfect camera because it's kind of big and heavy, so it can be a pain to drag around if you're on a trip or something, but I have gotten some beautiful shots with it:
