I heard varying things about epoxy floors, esp the DIY kind. I'd be interested to know how it lasts over a few years. You need to do proper concrete prep too..
I was gonna go with these guys:
Garage Storage Cabinets | Shelving | Flooring | Clever Quarters
They lay down a truly professional floor with a 25 year warranty. I'm sure it's way better than the DIY solutions, of course, it's also way pricier..