Two tone paint scheme with a third color 10" or 12" horizontal center strip looks good. Bottom darker gray ( hides dirt) red center stripe then a lighter gray on the top half.
Floor: If possibe, clean the floor with a good acid stripper then epoxy paint, this will keep any oil etc. from soaking into the concrete, easy to sweep up and hose off and looks good too.
Shelving, to maximize floor space, keep and floor shelf's to a minimum I would have 2' deep shelves from the ceiling using 1/2" pipe as the vertical supports.
Storage: I found a couple of good and solid wood throw away kitchen base cabinets and a chest of draws that worked well.
Fire: A fire cabinet for your paints and other flamables...a smaill galvanized trash can for a used rag can with lid and ABC fire estinguisher(s)
Door: Confirm you have a fire rated door between the shop and house.
Alarms: Carbon monoxide is a must as weel as a smoke alarm...However, you might want to have away to disarm them while working in the shop and rememeber to re-arm when done.
Work bench: Heavy duty with a hard work surface and decent vise, at least 6 outlets with overhead lighting.
Lighting: Try to find an electrician that is pulling out fluorescent units, this time of year you may come across a school that is replacing lighting....the more lighting you can get the better.
Outlets: 8' wall spacing is fine, be sure to have a ceiling mounted retracting cord reel that is a plus.
Heat: I have a simple 220v fan forced heater that works well as long as I fire it up at least an hour prior to using the shop...also works great as a quick drier for rattle can painted parts.
Air: Medium duty vertical compressor, running schedule 40 plastic pipe along the wall is easy to do being sure to use an air hose with and ID that will not restrict the necessary psi to the air tools.
Fans: I have a 30" fan mounted at the top of a wall next to the ceiling, this keeps air moving an exhaust fan is a must too that will removes fumes.
Exhaust hose: Make something up so that you can stick a hose over the exhaust while running the motor inside ( Be Sure to do this w/o and exhaust leaks but you already know this.)
Lift: Be careful what you buy as lot of it is junk...I would recommend a simple 48" mid rise scissor lift...this is high enough to be able to work on brakes w/o bending over and sit on a low mechanics stool to work under the car.
Mural: When I worked at the VoTec School we did a large shop mural using a projector to set an image on a wall then just did a quick loose outline of that on the wall, when done it looked great from a few feet back from the wall. ........I have a photo somewhere.
Refrig: An under counter bar type Is a must have but keep seating to a minimum or you will end up with a neighborhood man cave club house.
......I've built so much over the years ( replicars and home renovations) ) I would be glad to come by and check it out and give additional suggestions.