Starting on basement have a few 'getting started' questions

I have a basement that is 23 x 17 x 9 and is already completely finished with paint, carpet, etc... I want to make this room into a theater with the main intent being to watch sporting events, play some video games and watch movies as well.

I have read a ton of posts here and looked at lots of pictures as well. I really want to go the projector route, but am concerned if it will be the best for my primary viewing. I plan on putting in a riser and some wall panels for sound, sconces, etc...

My first question is about layout. In the attached picture where should the screen go? There are advantages and disadvantages to each location. Putting it on the wall between the the stairway door and closet door makes it easier to run wires, locate equipment, etc... but, I'm not sure if the stairway door would pose any problems. There is no physical door going to the stairs. The closet door will remain closed obviously. The far opposite wall might be good too, but wiring will be difficult, plus I would have to fit the riser between the two doors mentioned on the opposite wall.

Wow. I am really embarrassed by those first measurements. I went off the 'plans' and I think he included the closet beneath the stairs in the overall measurements. I went down and measured it myself now that it is finished and here are the dimensions. 16.5 x 18 x 9.

I know a square room is bad. This is very close to a square room, but at least I have 9ft ceilings.

Here is an accurate drawing.

Thanks for the link. I'll need to do some reading on that stuff to understand it all.

I was hoping to get something like this down in the basement.

I'm not sure what the dimensions are or how close it would put my 1st row of seats.

Maybe I am listing it the wrong way then. It is 18 x 16.5 x 9. The wall on the left in my drawing is 18 meaning the speakers would fire down the 16.5 wall. I tried to list the wall dimensions out to the side of the wall. Sorry for the confusion. Does my 1st post question still apply?

Here is an attempted sketch. Just some random thoughts put out there. I am still reading everything I can at this point. I want to start soon though.