What games do you play? What GPU do you have? Will you be upgrading your GPU anytime soon? What is your size preference? What is your budget?
If your current GPU runs your current game at 60 FPS or less just about any monitor will work.
If your current GPU runs your current game above 75 FPS or more...I would look at a 144hz monitor.
Bigger isn't always better, 23 -25 is the norm for a gamer, while some run 32" or larger (I tried it and it hurt my eyes)...
Then there is always multiple monitors...while very nice it is very expensive....
If this didn't help, answer the questions above and I am sure you will get some good recommendations...
Good luck,
johnny