What I'd like to do, and what I actually could do are different - mainly due to my migranes, glasses and asthma.
Tech - I'd love to be a rec mech officer with REME Light Aid Detatchment. Specifically the heavy units. Something really interests me about recovering MBTs under fire.
Or, tanks -
The RAC (no, not the car mechanics firm...) Again, mainly so I can work with the tanks.