I concur on the subpanel but it is probably too late now if you have run the wire. I think the cheaper route is to use GFCI receptacles. I also think you may be confused on GFCI breakers which go in the breaker box and the GFCI receptacle. The GFCI breakers are subject to nuisance tripping if the wire runs long distances and also from motor loads. Many people have that trouble with outdoor spas and they use a regular breaker in the panel and then use a GFCI breaker as the disconnect in a box at least five feet from the spa. In your case, with the wire run, put the GFCI receptacle as the first one in the garage on each circuit and follow the instructions. Don't put a bunch of GFCI receptacles together by the breaker box as you had asked.
You have a big garage and it sounds like you wired it in based upon a residential general lighting circuits for every 500 to 600 sq.ft., but your garage may have special requirements. I would spread the lighting over two circuits and may want two circuits around the workbench when you figure grinders and all the other tools that may go there.
You may want a separate indoor circuit for an air compressor and will you add a welder? Be advised that if you put the compressor in a separate building it will have to be wired like a detached building with buried conduit going to it with a disconnect and ground rod at the structure. You may want to go ahead and run that wire through the garage before you cover everything up.
I am assuming that your garage is attached to a residence or else you are definitely required to treat it like a detached structure with a subpanel, etc. Pull a permit and have an electrician double check your work. Good luck.