Okay, I'll confess... my house is 5400 sq ft and it doesn't seem uber large to me because of how it's laid out. We're on 5 acres.
It was custom built, not by us. It's a 4 bedroom "normal" looking house, but an additional in-law suite and a playroom/bedroom over the garage. The craziest thing, which I happen to love, 5 1/2 bathrooms - lol. Master has one, dd's room has one in her room, then a hall bath for ds's room and what is dh's office. Then a half bath downstairs, the inlaw suite has a full bath as does the playroom.
I don't like going to the office everyday, so a lot of times I'm working in the living area of the in law suite. The playroom is fabulous for sleepovers - with teenagers I'm happy not to hear the girlie screams all night long.
I'm hosting thanksgiving this year and we have enough room to have 11 extra people sleeping over.
Once the kids are grown and gone it will probably feel way too big. That being said, we've lived in big, we've lived in small, and we always acclimate to our space, but never have enough closet space.