I have a chair, but it's not pictured. It's a crappy chair. I don't sit in front of this computer much anymore (too busy working).
The sub is sheilded, and since the display is LCD electromagetism isn't really involved.
The speakers angle upward, it's more for background than serious listening. The Sony MDR-7506s are what I use when I want to do some serious listening.
I can pull the keyboard out closer to the chair, leg room typically isn't an issue.