Doug, I see you have sheetrock done. Did you pre-run some speaker wires so you could mount some surround, or left/right channel speakers in the walls for flush mount? I did some Radio Shack flush mounts and a Radio Shack Sub-woofer to augment my stereo (IT IS A GARAGE after all
).
Also, did you pre-run some air lines so you have jacks in the popular corners where you might want to plug in for some air? As for the floor, I defer to G.R. but would think filling the cracks and then doing some abrasive leveling and letting it all cure might allow for 2 part epoxy. Then again, I am becoming a Race-Deck convert over time.