Seats are assigned when you buy tickets in all the cinemas I go to.
I generally like around the middle, I'm not sure why though

That shits me when a cinema does that, but sometimes they'll ask your prefered area and you might be lucky and get it, if not they'll get you close. Although usually once everyones in and its clear nobody else is entering everyone swaps around XP

But yeah my local movies dont do assigned seats.

So you and me would either be sitting next to each other or fighting for the spot :P

I went on their cheapest day, $8.50 adult ticket.
Mind I never get popcorn or drinks anymore, that puts the price past $20 >.<

middle middle, and I just saw xmen last night

Last time I saw an X-Men film was when I was in Belgium in 2009 :P

The very center; not too close to the screen, not too far. Juuuust right. The "Goldilocks Zone", if you will.

I like the edge of the habitable zone ;p

Yep. Back row center. At least the wall is civilized enough not to throw Milk Duds or leave its phone ringer on.

Prime position for throwing milk duds at others though :p

middle in the row where the bars/railings are so a) no one is in front of me and b) i have somewhere to put my feet (not much space between your seat and the one in front of you)

I know some cinemas have that railing about halfway through, usually about where the entrance and exit is, but my local movies are smaller so that spot would put you closer to the front than might be comfortable. Almost into the zone where you need to keep your neck tilted to see XP
I've got a friend who shares your favourite position, though he goes to a large multiplex where the bar-row is far enough away from the screen.