Pilots: Do you prefer high-wing aircraft, or low-wing aircraft?
Personally, I prefer rotarty-wing aircraft. 
But that’s not an option. I prefer high wings. Upward visibility is somewhat limited, which makes it a little more difficult to see airborne traffic. On the other hand, a great thing about flying is the view. High wings are better for sightseeing. In SoCal I liked having a bit of shade when I got out of the plane, and when flying as well. It got a bit warm down there. In rainy climes, a high wing keeps the wet off. Also, many or most high-wing airplanes have two doors. It always seemed a little undignified to have to slide over from the passenger’s seat. Besides, I earned my spurs in a Cessna.
Fixed-wing aircraft I’ve piloted are: Cessna 172 Skyhawk, Cessna 182 Skylane, Grumman AA5 Traveller II, and Piper PA-28-235 Dakota. The Grumman (my first five hours, BTW) with its sliding canopy was cool. Great visibility, and the pilot and passenger(s) got in on their own sides. Ground handling with the differential braking was great. As I said, I got my license in a Skyhawk. I like the downward visibility, and the opening window. I’d always look at those wings and think ‘fat with lift’. The prosaic old Cessna always seemed eager to get off of the ground. The rear window, often not an option on low-wing aircraft, was nice as well.
Helicopters have truly great visibility. Too bad they’re so expensive.
I’m a low wing guy.
Took my first lessons in high wings, but having flown something like 50 types of aircraft ranging from a J3 Cub to a MiG-15, I now prefer low wings.
As an instructor I spend a lot of time in airport landing patterns, and I prefer to be able to see where I’m going. No two ways about it, low wings are better in the pattern. Not that it is a major factor when you get used to a high wing, but I still find it bothersome to have my view obscured when turning base.
Much easier to fuel a low wing and verify fuel quantity - no need for ladders. I knew a guy who got killed with this as a factor. He had bad knees and couldn’t climb up to check fuel without a ladder. One day no ladder was available where he was pre-flighting, and anyway his partner was supposed to have filled it up earlier that day. You see where this is going. Also easier to detect a fuel leak in flight because you can see the caps on a low wing.
People say it’s easier to get in and out of a high wing, to which I say nonsense. I always trip over the gear, but that’s because I’m a low wing guy! My favorite planes for ergonomics and visibility are Grummans. As Johnny said, the sliding canopy is really cool. Sitting down in one is like getting into a fighter. They also have the best panel vents on hot days - way better than any Piper or Cessna. The Grummans also have great visibility because the pilot seats are raised. Very different sight picture than most other aircraft.
When students ask me which they should train in I tell them it doesn’t make much difference. You get used to whatever you fly.
High wing. So much easier to enter end exit (especially in the rain), not to mention the downward visibly.
My favorite by far is the super sexy Cardinal Retractable (C177RG). Loved flying that aircraft more than any other.
I can see that, and it’s a good case for low wings. But except for pattern work, I liked to get away from the airport. During training my instructor sent me to Henderson, NV (from WJF). I was downwind, and I looked aft through the Skyhawk’s rear window to see a retractable swooping in behind me on the 45 and gaining on me. I’m glad I had a high-wing with a rear window in that pattern.
I have bad knees, and it’s much easier to check the sumps on a Skyhawk. The primary one I flew had a step at the firewall and a handle above the canopy that made it easy to step up and check the fuel. Otherwise there was a lightweight aluminum step that stowed in the baggage compartment.
I never had that trouble, even with the wheel pants. To get in I’d step on the step, and to get out I’d just put my foot on the ground. Getting into a low-wing was no trouble either. I just didn’t like sliding across the seats.
One minor annoyance on a Skyhawk or Skylane is that you have to watch where you walk. Otherwise you might get a diamond pattern on your forehead.
The AA5 was the best. No seat-sliding. Step over, flip up the seat cushion with my toe, and slide in. If I ever buy an airplane, an AA5 or an AA1 (with the 150 hp conversion) would be very tempting.
Did you ever find ‘sight picture’ a little redundant? (It’s the phrase used, but it’s always made me smile.)
Great advice.
But you voted low-wing? 
Think Mach voted low wing. I prefer them where them where God put them on birds.
Maybe Mach will vote for you.
Biplanes!!
Not an option! Only completely hetero planes in this poll! 
Now that’s just being indecisive. Don’t even get me started on that von Richthofen with the tri-wing!
Hater! Some of us like it both ways! It’s a legitimate flying lifestyle choice!!
Besides, some of us need all the lift we can get.
In little planes that I have flown:
Gota get there = 601 Aerostar In the middle wing, snerk
Play fighter pilot = Swift Low wing
Got to get in where and haul what out??? = Cessna-180 High wing
Easiest tail dragger to land = Stinson 10-A High wing
See if I can pull the wings off = Pitts S2B - 260 Bi Plane
For me it depends on what I wanna do…
I don’t fly in the rain, so that doesn’t matter. But at my age and with my knees, a high-wing is easier to get in and out of. Plus, I love watching the ground, and low wings get in the way of that. Judging turns in the pattern just isn’t a problem in my experience (maybe because I learned in a 172). As for checking the fuel, there are high-wing, short-gear, low-fuselage LSA’s that I can see into without a ladder.
That said, I only fly a low-wing these days, because it belongs to a friend with a bad medical and I get to go along with him all the time to keep him legal.
Low wings (see Mach Tuck’s post)
Low wings. They pay better. The vast majority of the time I’ve been paid to operate an aircraft it’s been low wing. I have had a smattering of paid-for mid- & high- wing gigs; < 10% of my total though.
I did start out in a C150 & still have a soft spot in my heart for them & their cousins.
If I was to buy or rent a light single it’d almost certainly be a high wing & probably a tail dragger.
From light piston twin on up to big jet, the choice is pretty much made for you. While high- & mid-wing examples do exist here & there, they’re by far the minority.
Like **GusNSpot **said in many fewer words; the optimal wing count & location depends on the mission.
One thing with high wings when turning in the pattern: You don’t get the sun reflecting off the upper surface into your eyes.
Why no choice for “happy to fly either”?
Because that’s axiomatic!