Depends what you are buying for haha. If you are looking purely for a gaming machine the best value would probably be the 360 followed up by the Wii. Not paying for anything extra with those and what ya get with it are purely for gaming. Good for me considering I already have a very capable blu-ray player in my laptop which makes that function of the PS3 obsolete in my buying decisions.
Now if you are looking for the best bang for you buck on the most well rounded machine then I would say the PS3 definitely. High end hardware, blu-ray player, ect ect. Followed by the 360 and Wii.
It just depends what you are looking to get. But considering most of us here are gamers you best choices for gaming features and of course games is Wii and 360. If extra stuff is necessity then get the PS3.
And note I'm not banging on the PS3 I'm just going for what has most games, most feature attributed to games, and the price allocated to get the best deal imo.
