Personally, I always thought there was a big difference in picture quality between analog and digital connections. So, you may want want to look for a monitor that has a DVI input. Of course, you also need a video card with a DVI output -- which, most do, but it's best you check anyway. Unfortunately, monitors with DVI inputs tend to be around $30 or $50 dollars more expensive than their analog-input-only counterparts.
Contrast ratios are a bit of a joke. Manufacturers tend to take enormous leeway in writing that part of the specification. So, a monitor with a supposed 700:1 contrast ratio may have an actual ratio of only 400:1. The manufacturers really do exaggerate that much.
Even though there a lot of different brands for flat panel monitors, there are actually only a very few number of manufacturers that actually produce the panels that go into the monitors. So, monitors across manufacturers that use the same panel can have very different price points (which are due to differences in bezels, stands, name brand, etc.). If you're willing to do the googling, you can find a lesser name monitor that uses the exact same panel as the better brands.
"Brightness: 220 cd/m²" is fine. The larger the screen size the lower the brightness cd/m² tends to be because of the increased area.