Same thing that stopped me from getting a 360 this year. Paid online service.

The only thing that could keep me away from Halo is if it went Motion Controls Exclusive. The only thing that could keep me away from Nextbox would be if Halo was gone forever.

But as far as "features" I don't want to see, it would be digital distribution replacing retail packaging. I'm too much of a gamer to give up gaming if it goes digital distro, but I'm an old timer who has the crazy belief that the thing you buy should be real, be 100% yours and if you so choose you should be able to sell it, trade it, trash it, burn it, send it into space, or even take it apart modify and run it on an emulator. I really don't want to see publishers use the convenience of digital distros or the cloud as a way to take ownership rights away from us.

Digital-only games. If this happens, i'll quit home console gaming.

I'll never pay for online.

Microsoft is out of the picture due to paid online and no exclusives that interest me. I'll buy the PS4 when it's available for around ~220€. Won't buy if they put online into the PS plus service, which I suspect they will absolutely do. Maybe I'll buy the PS4 anyway, for the singleplayer experience, but at 175€ max then.