Many monitor sellers won't let you return them, so check that before you buy anything. Have you decided on the computer?
The post with dot pitch is a good one. With my 30" I have to increase the DPI settings to make the text a little bigger because of the small dot pitch, but the upside is great resolution.
As I said before I would get an inexpensive but workable system and decide what you really want when you are in a position to do so. A pair of 24" can be had for less than a grand, and you can get a pair of cheap 20" monitors for very little. There are no "great" 30 inch monitors right now, they all have one problem or another. I like my NECs but at just under $5k for the pair I wouldn't recommend them to any new trader. For the price the 3007wfp-hc is not a bad choice if you just want one large monitor.
I would buy a simple setup with two monitors and then if you become serious about this after several months, then use that setup as your backup computer. Eventually you can spend your profits on whatever computer and monitors you want. If you really want to spend money now I would go with a pair of 24" or 26". They both have the same resolution, so the dot pitch is just a little bigger on the 26".
A professional trader should have two computers, two separate internet connections, and battery backups that will last long enough to get you out of everything.