I'm ambidextrous when it comes to playing any kind of instrument or doing any kind of medical work, but right-handed when it comes to writing (if you don't want my writing to look like a 5 yr old did it!)
I am right handed, but forced by my job to work left handed. Nearly all of the surgeons I assist are right handed, so I must be able to manipulate instruments, cut and tie suture and sew left handed, as well as right handed.