Hate the poll, but love the topic. I'd add "watch at a bar/party" to the list as that is also a different experience for many (for some I imagine that's just like "watching at home"). And already we have some like me who say, "it depends".
The ultimate experience is live, IMO. If it's a great game, and you have great seats, and the weather is great, you can't beat being at the game. By great weather I just don't mean "warm weather". I think the Dolphins "let it snow" game was great live-experience weather, same with the Raider 51-3 game. Being at a game where the weather mattered, and the Bills won, is usually a great experience IMO. OTOH, a crappy game is best watched at home, no matter what the weather.