I did a big of HD work today on my new iMac and I have to say it worked rather well and looked great.
My opinion, the new iMac looks greats the "glossy' screen in real life use has no reflection problems in a regular home setting. Ive been using this thing pretty much non stop for the last three days.
Macs in general have never been gaming systems and most likely never will be gaming systems. Gaming gpu's are become a joke they are not cost effective at all, consider you can buy and entire PS3 for the same price as a 8800gtx video card.
Even hardcore pc gamers like myself can't justify having to upgrade every six months ot play pc games.