Depends on where you set it, where I'm from the wind is almost always the determining factor, when you're in thick trees and wind isn't a factor, then you set your tent wherever it fits. Which direction you're facing depends on the terrain and your exposure.
When we went camping a couple weeks ago, we set one of our tents up specifically to take advantage of the view:
Another determining factor for how you set up some tents is how level the ground is. If the ground is not perfectly flat, you want to orient your heads uphill, this way you don't wake up with a head rush, or if you're in a tent with a bunch of people, you don't all roll over and end up on top of the poor souls who got the spot furthest downhill. If your foot print is round, then you can still put your door wherever you want it, then set up you beds inside with the heads uphill.
Water is yet another factor when setting up your tent, you don't want to put your tent anywhere water might flow or accumulate. Low spots are great for protection from the wind, and are often flatter, but if there's rain in the overnight forecast, you might consider setting up on the high ground so you don't wake up in a puddle.