I agree completely with Tony Fabris. It's near impossible to give a set date for when a piece of software will be released.
Platforms change, drivers change, etc.
Christmas no less, and look what it got them. Countless patches have been cranked out, and with almost every one there was something else that needed fixing. However, some companies do manage to deliver on their release dates. Lucasarts in particular has shipped X-Wing vs. Tie Fighter and Jedi Knight on solid release dates, and they needed maybe one or two patches. There's my two cents.