"... and now I think 'Hmm, maybe a 60″ would be nice.' Is that wrong?"
It's not wrong, but have you ever noticed you can make the TV you already have bigger by just scooting your chair closer? Only get a bigger TV if you watch with enough other people to make it impossible or inappropriate to move your chair forward. But if you do want to buy a new TV, get a nice one. Go all out if you can and get something extravagant that just became available today. If you're watching alone or with one other person, and you want bigger, but you're thinking of getting a relatively ordinary but larger TV, may I suggest these?