How Much Better Is The New Iphone Than The Old Iphone

Im thinking about getting the iphone. I was wondering if i got the old iphone, iphone 3g would it still be as good as the newer iphone? Like what are some of the things that the new iphone has that the old iphone dosnt? And how much better is the camera on the new iphone? because i love taking pics, so is the old iphone a good enought camera? thanks!