Yes insolation is important, I would only need to do the ceiling because the wall is a cavity wall with insulation between the bricks and the blocks...
Im going with porcelain tile.... I think thats the best, it's durable, won't fade, you can replace a tile if you needed to without redoing the whole floor.... And I think it looks good.
Edit: I'm still on the fence between tile and Epoxy.....
I don't keep the garage heated all the time.... I have a 45000 BTU furnace that heats up that small garage in no time. Plus the walls are block and brick so they're pretty thick, I would just need to do the ceiling.
If I were to work in there full time I would defiantly insulate it.