I own an XBOX and I love it. I made an XBOX 360 game and I had fun making it. The XBOX 360 is a great console and with the news of a newer better console it has people like me very excited about the release. While I love the console as a developer there are a few things that I really dislike and if these don't change Apple could come in and sweep the console market away from Microsoft.
You are probably thinking that Apple would never produce a console to directly compete with the XBOX or Sony and you are correct. Apple did produce a console in the 90s and it bombed. However, they could produce a product that interacts more with TVs and has the ability to play games on it. This could be devastating for Microsoft.
As a developer the costs of producing an XBOX game are simply way too high. There are 3 tiers in which you could develop for: XBOX 360, XBLA, XBLIG. XBOX 360 costs the most money(millions of dollars), XBLA is the next expensive(~750k), and XBLIG (~$100 and a whole lot of heart).
This setup is more the old style of producing games. The style where you had to ask for a whole bunch of money and then produce your game. However, times have changed. People now want to be able to make games for less than 100k. You think you could do this on XBLIG but you can't use good engines like Unreal or Unity. So essentially you have to code a game from scratch which takes way too long and the quality is nowhere near as good. This is my biggest gripe with developing for XBOX. Please let us use Unity or unreal to make games for XBOX 360.
Now where does Apple fit in. If I were to make a guess I would say that Apple might make something similar to Apple TV but have an app store on it. The app store would be tailored so you could play games on your TV and use your iPhone or iPad as a controller. If Apple does this they will seriously give a blow to the console market. On the app store you can create games with unity or unreal and a myriad of other great engines. So instantly there will be more games on the TV app store and then more people will play that versus the XBOX. As a developer I have to go to the places that have the best engine support. You can't compete by coding game from scratch in native code. It is just too much work.
News of the 720 has sparked the next console cycle. If Apple decides to enter it could be problematic for Sony and Microsoft.