70 is way too big.
I have a thirty something/close to forty. I wish I had gone one size higher because I could have afforded it (when I got to the store I found that the advertised price had dropped from what I had found on the internet) but decided to be fiscally responsible rather than go all out. The thing was, I could have gone about two more sizes up and stayed within budget, but I really felt that it was just too damn big.
And the TV is a big deal in this house, not to mention my Dad only has one eye so a bigger screen was a major factor in that purchase.
I remember when the really large flat screens first came out and a friend of mine's family purchased a HUGE one. It took up almost one entire wall in their very small living room and was incredibly uncomfortable to watch, not to mention the pixilation issue, since TV service had not caught up with the TV technology yet.
Sometimes, bigger is not better and as much as such statements are sacrilege to many men, TV's are one of those things.