I've used my projectors (AE100 and latterly Z2) for everyday TV watching ever since I first had them, and wouldn't go back to a conventional (even if large-screened) set now.
I do have a small LCD monitor though, which I use for setting up Sky+ and other recordings. It doesn't make sense to fire up a projector just for a couple of minutes.
It seems to me that there are three factors to consider:
You have to be able to achieve a reasonable blackout or near blackout, and (just as important) you have to not mind doing your casual TV watching in those conditions. (Though I do find myself sometimes using my monitor as a background TV, which is another good reason for having a second smaller screen.)
You have to accept that you'll get through projector bulbs faster than a user who just watches the occasional movie.
With an LCD projector you have to be aware that in some circumstances prolonged use can cause deterioration of the polariser filters and possibly the LCD panels too. Ventilation and airflow are important, also regular cleaning.
But - as I said - I wouldn't go back!
Bert
www.bertcoules.co.uk