Yes the term Fully Loaded is over-used but folk use anything to sell cars these days. I interperet Fully Loaded as most people would on this forum as 'many optional extras' selected. It's easy to see through those false claims. My old 335i was indeed fully loaded (10k extras) and the X3 is also (similar extras if not more).
Fully Loaded is what you want it to be. To me its a shit load of extras (to some its a CD Changer!).
Current -: 370Z GT Roadster / Qashqai+2 Tekna 1.6dci
Gone -: BMW X3 3.0d xdrive M Sport; E46 330i M Sport Coupe; Mazda RX8 231; Nissan 350Z GT Roadster; BMW E90 330d M Sport; BMW E92 335i SE; Maserati 4200; Nissan 350Z; Honda S2000; Astra Coupe Turbo; Ford Probe