The Xbox One is not backwards compatible, and, in all honesty, that's a deal-breaker for me.
The Xbox 720 event today revealed everything we know so far about the now-named Xbox One, so the rumors and speculations are mostly dead now. Unfortunately, the one rumor I didn't like about Microsoft's next generation console was confirmed.
The Xbox One will not be backwards compatible, and that poses a problem for long-time Xbox gamers. You can't play Xbox 360 games on the new console, and you can't even transfer the games you installed to the hard drive off Xbox Live Arcade. Think of all the money you wasted if you have to replace the console instead of placing the two next to each other.
The Xbox 360 was backwards compatible to a degree, allowing part of the original Xbox library to run on it, given you installed an emulator off of Microsoft's Xbox website to make it possible. That way, gamers who still liked their older games could still play them as long as the compatibility list included them. If the Xbox 360 had not been that way, I most likely would have bought Nintendo's Wii instead.
Microsoft should not make us have to choose between our current library of games and upgrading to the next step up. A lot of us don't have room for another console and don't want to have to buy a whole new set of games to go with it because the old one would need to be "archived."
If Microsoft wants us gamers to put money into their Xbox One, they need to give it a fix like they did with the Xbox 360. If I can't play the games I have now on the new console, the new console is a waste of money to me.
Perhaps with time, they'll see the problem and offer an emulator patch. That's how it always seems to be with Microsoft, delivering an unfinished product and then updating the software after consumers complain enough.
Is backwards compatibility enough of an issue for you to say "no" to the Xbox One?