i've played around with the sharpness settings on my television before. if you sharpen by 10% or less then sometimes the results do look decent for things such as video games and text, however even at a minimal level you still get little jaggies and inperfections where none existed before.
i'll say it again: i would suggest sticking with normal display modes.
Well you see, normal display with HDMI, enables AV mode by default. I'm always for default settings, but this AV mode does more harm with gaming than good. Of course theres aliasing in games, even when playing a PC game at 1920 X 1080. Thing is that AV mode makes artificial aliasing, basically you shouldn't normally see it, and the visible aliasing much more harsh.