I agree with Axman on the grain problems using the higher ISO. With the D3000 I would go for the AF-S 35mm, f/1.8 Nikkor. This lens will give you better results without breaking the bank. I don't recommend the 50mm D, f/1.8 because it is not a AF-S lens. Your camera does not have an internal lens focusing drive which is required with the 50mm D to auto focus. Shooting a band on stage in low light will require an AF-S lens to give you auto focus. The 35mm, is a AF-S lens and will auto focus with your camera. It is also sometimes difficult to get the AF-S lens to focus in low light. The Nikon auto focus system needs contrast to lock in focus. If the lens won't focus, move the view finder to an area that is close to your subject that has more light and contrast, press the shutter button half way down, let the lens come in focus, then move back over the subject and shoot. I would also always use the AF-S focus mode. I would also recommend you learn to use a monopod to give you that extra stability in low light and slower shutter speeds.