I cast my vote for 8th, however, like many other people have said it really depends on style of play.
I truly believe that LVG isn't going to turn around United in a season and that Liverpool is going to fall off. I think our biggest competition for the position we all want is Everton.
On a separate note, I think that Newcastle is actually going to be really good this year, and that from 4th to 8th will be within 8 points. We're going to have to play well out of the gate, and we need a win against Liverpool in that 3rd game. It'll take a ton of pressure off our squad and manager, and allow them to focus on what they are doing well vs what the flaws of the system are. Let Poch worry about the flaws, and let the players worry about whether or not their executing his plans perfectly. I think that a 6th place finish is quite possible, and 7th would bother me a lot, but it wouldn't be the end of the world. Especially if we're scoring against the majority of our competition and lot allowing clean sheets against us. 8th is where I really come along and say the gap is too much to overcome given that we have great players and on paper see no reason to finish lower than 6th.