The Nikon D3000 has a better display than most SLR cameras that have been on the market for around the same time as it. This camera has a TFT display, whereas most digital cameras of this type and age have an LCD display. TFT LCDs provide better image quality and higher resolutions to earlier LCD displays but their limitations are narrow viewing angles and poor vislibility in direct sunlight.
This digital camera's display (TFT) is actually the best display amongst all SLR cameras that have been around for more than two years.
The worst display across comparable types of digital camera is LCD.