Digital Art: Photography, drawing, publishing
Get the highest resolution (a minimum of 1280x1024) and the largest screen you can afford. This will offer you the truest image, the most detailed views and the biggest canvas to work with.
Your LCD should also be able to display millions of colours, since the more colours your screen can create at one time, the more realistic, detailed and rich your work will be.
While it may not be true in every instance, when it comes to LCDs and art, bigger _is_ better.