The Nikon D3000 has a better sensor type than most digital cameras of this age and type. This digital camera has a CCD sensor type, whereas most cameras that are a comparable age to it have a MOS sensor type. CCD sensors produce high quality, low-noise images but consume a lot more power than CMOS sensors. CCD is the most common image sensor type used in digital cameras.
A CCD sensor type is actually the best sensor type amongst all similar spec digital cameras that have been on the market for a comparable time to the D3000.
Amongst comparable types of digital camera the worst sensor type is MOS.