For 17-inch monitors, it's usually between 15.8 and 16.1 inches. Screen resolution is really how many dots or pixels can be displayed on the screen. Most computers will offer different resolutions, although the most common are 800 x 600 and 1,024 x 768 pixels. The first figure is the number of pixels horizontally across the screen and the second number is the vertical. Any decent 17-inch monitor should have a top resolution of 1,600 x 1,200 pixels, although you'll get the best results at 1,024 x 768.
Refresh rate is a techno-term for how fast the screen image is updated.
Because our eyes are not great at perceiving rapid changes, the screen looks like it's constant. However, if that refresh rate slows down enough, you start to see the screen flicker and it gets really annoying after a short while. Ideally, you want this figure as high as possible but, since it changes depending on the screen resolution you choose, always make sure that it is at least 75Hz - more is better. Also, as the monitor relies on your computer's graphics card, make sure that card is good enough to do the job. If you own an Apple PowerMac computer, check that the monitor will run with your computer.