I would definitely expect housemates to contribute if they want a tv in the living room.
As to whether or not to get one, it depends what, realistically, you foresee you will spend your time doing instead of watching tv.
If it is something more worthwhile than watching tv, such as reading, studying, doing a hobby, or socialising down the pub, then don't get one.
If it is something less worthwhile than watching tv, such as perpetually masturbating or ****ing around on the internet in your room like a loser, then do get one.
That is my honest advice.