I personally would not get a TN, they make my head hurt just looking at them for an hour and that's only because I'm so used the the neutral and uniform display of an IPS. A VA based panel will be a more striking option.
My friend had the NEC 20WGX I shall point him to this thread and see if he can advise on you a suitable 24" as he upgraded to a 24" I believe it was an Iiyama but I cannot remember.
I myself have had the Dell 2007WFP, the competing, non glossy sister to the NEC 20GWX2 and when I went 24" I had many, many 24" screens inc the 2408WFP before sticking with the Hazro.
Like you I game too but also do professional work so colour and quality was just as important as gaming performance.