That gets complicated, because the details you want to look at are: glossy vs. matte screen finish, viewing angles, static contrast, ghosting time, and input lag, which can vary considerably for both monitors and tvs. If you can specify the exact model of TV you have and what model(s) of monitor you're considering buying, I can try to determine which would be better for gaming. As far as I'm concerned, a 120hz monitor is only worth it if you plan to use it for active 3D or you can get at least 80 fps in the games you play. A 60hz monitor with better screen finish, viewing angles, or static contrast compared to the TV you have might be worth it, though.