Since I don't have an 80" TV, 1024. Unless you're sitting so close to a 55" TV that you can see the individual dots in 1080, 4k isn't going to to do much as far as what you see.
If you're recording something for posterity - your baby's first steps, for instance, you might want to go to 4k, because by the time she's old enough for you to embarrass with the video, 4k will be an old technology that almost no one uses any more. (How many people still have 8mm silent film from when they were kids 60 years ago? Even when my daughter was born 40 years ago, we had sound.)