This is similar to your other question in that you're asking something that is very subjective. How much brightness you need depends on your environment. Do you almost always game at night, or with thick curtains closed. Do you game in a basement or a room with tiny windows which never get direct sunlight? If any of those are true you do NOT need bright monitor at all and in fact it would be much better for your comfort and long-term vision to turn your brightness down to 150 or lower. If your gaming at night with just a dimmed light on, even 100 cd/m2 is actually more than adequate and saves your eyes.
If, however, you're likely to be gaming with direct sunlight on your monitor, then you want the brightest monitor you can get...