^ Like all things Apple, nobody knows.
There's increasing evidence that Apple may replace the tv with something else entirely -- existing or to be announced.
- Introduction of iTunes LP yet no support for where it would make the most sense: on an tv
- Slew of launches today, without even a firmware update to tv
- No reference to tv as supported by the new Apple remote
- Reference of MacMini as an "Entertainment Center".
- Addition of a VESA mount for the new iMac. The 27" iMac could replace a bedroom TV + tv and it could be one in the line of larger iMac's to come
Apple will not give up the living room but the odds for an update to the tv seem to be getting slimmer with each new Apple announcement and the increasing gap between updates.
So.... if you want an tv, I'm sure Apple will support them for at least a few years if they discontinue the device: get one now. There's little point in waiting.