Whats the budget?
Are you doing the drywall work yourself?
Looks like some purging (the boxes and stuff) is first.
Patch the ceiling drywall.
I would tear all the plaster/drywall off the old fireplace up to the ceiling. Sandblast or otherwise clean the stone/brick and see if you like the look. If you don't like the look, I would drywall over the brick/stone rather than painting it.
Have the concrete floor ground smooth and stained or just carpet it.
Replace the trim on the windows to make it consistent or just stain/varnish if it already is.
Wire and install a TV above the fireplace (power and cable).
One problem you may have (can't see it in the pictures) is power for the machines. If you are installing 6 machines, you should have a dedicated electrical circuit or 2 installed to power them. It's likely most of your basement is on one circuit and 6 machines, the lighting and other electrical item (kegerator, for example) will consume that whole circuit causing the circuit breaker to blow when you try and run them all at once.