So, you are standing at the foot of the bed facing where the headboard should be.
Do you usually sleep on the right or the left?
I always sleep on the right side of the bed.
The center.
Seconded. I sleep in the middle of my bed with my duvet heaped ontop of me.
The right side of my bed is up against a wall. I generally sleep on my left side, with my back to the wall, in contact with it, and with my head pointed toward the footboard.
It just feels right.
To the left, nearly against the wall.
Not having my bed in a corner against two walls seriously bothers me. I’ll go so far as to disassemble hotel room beds and relocate them to a more suitable position. Actually, if you do this with both beds, you get quite a bit more usable floorspace.
Whichever side is nearest the alarm clock and the phone.
Facing my bed, the left side is along the wall. Currently, I have a water bed, but for some reason even though all the tubes are filled with the same amount of water, the right side sinks down about 3 inches lower than the left side. I usually sleep on the low side, because it’s harder to get up onto the high side without rolling over and feeling like I’m falling.
If it was the same height, I’d sprawl across the middle, taking up as much space as my little frame can possibly fill.
-foxy
I sleep on the right side when hubby is home (he’s gone for work about two nights a week), and on ‘his side’ (the left) when he’s not home. This is because the most comfortable way for us to snuggle is with both of us laying on our left sides, in the spoon position. So when he’s home, we have to sleep me on the right him on the left for this to work. However, his side of the bed has more room on the floor, for getting up in the middle of the night to use the bathroom; hence, I sleep on his side when he’s not home. I also hog all the pillows when he’s not home. 
Right side. Unless my Wife and I are at a hotel. Then, for some weird reason, we always seem to switch sides.
Left side. I don’t recall at what point in our marriage it settled this way, because when we first married, I had the right side. In hotels, I pick the side closest to the phone and light switch, unless I’m with my sweetie, in which case, we sleep like at home.
if i’m by myself then smack in the middle taking up as much of it as possible 
If i’m sleeping with someone else it depends on who is waking up first in the morning, they get the outside.
The top side.
Center or right side. I’ve found myself awake at night firmly against the wall on the right side of my bed more than once. Not the most comfortable position, but better than going too far left and falling on the floor.
Actually, the question is somewhat moot. My bed is so small it can barely be said to have sides.
I fall asleep on the left side, but I toss and turn during the night so I could end up anywhere. Usually end up in the middle.
I range between the center and the left when I’m alone, and stay on the left when the BF’s around (luckily he seems to prefer the right).
When I slept in a twin bed I could keep it against the wall (which always happened to be the right side), and I found it very cozy to sort of sleep right up against it. I kind of miss that, although I don’t miss the way I used to kick my knee against the wall every once in a while.
The side facing the V
At my age, the side closer to the bathroom.
Actually, whichever side isn’t taken up by a cat or two. Or My Guy, who’s in there somewhere (he’s the one who’s not very furry). We have a very fun bed.
I’m on the left. This one is simple. It is the side of the bed with the reading light. It is also near the bookcase. My next goal is to get a larger bedside table with more room for books.
I sleep on the right side of my own bed, mainly because Hubby sleeps on the left and refuses to even consider trading sides with me. (20 years and counting now…)
When I sleep on my own somewhere else, I’ll sleep on whichever side has the most convenient place to put my glasses. I’m blind as a bat without them, so I don’t want to have to hunt for them when I’m waking up.
All over.