It seems it's down to Infinity, Infinite, or just Xbox. Personally, I still like the idea of just going with Xbox. They're already keeping it simple by calling it a new generation, so just call it the new Xbox. If I had to guess, though, I think they'll be tempted to give it something more. A console is different than a phone, as these things last about 7-8 years now apparently (if you release a new version of a product every year of course you don't want to bust out a bunch of names or numbers, but a long-term product like a console I could see it).
Out of Infinite or Infinty I'll go with Infinite. I like the tagline potential the best, plus it doesn't sound like Comcast cable. Also, Infinite was something that was discussed as far back as 2011, and it was talked about heavily around CES 2012. To see this old name get brought back now makes it seem more likely. And, yes, I expect them to turn the 8 in Windows 8 sideways to form the infinity symbol when it's announced.