Make sure you take a look at both aperture grill and shadow mask monitors in person before buying one. I find the two lines (Which are extremely thin) to be very annoying when viewing applications with light backgrounds. Most people can seem to ignore them, however, there are enough people who find them annoying that I would at least see one before making the purchase. It's much harder to notice the lines in games unless you are trying.
As a side note, while you're checking out the different types of tubes you should check out different brands of monitors. Seeing monitors in person helps you make the best decision. If my friend didn't purchase the monitor I have now before me then I wouldn't have bought mine. I assumed that the quality was not up to my standards because of it's low price; I was wrong. It isn't the greatest monitor, but I was willing to sacrifice a little quality for size.