Your residency application is a great reason, nay, the only reason, for you to volunteer to serve your fellow classmates. I congradulate you on realizing this. Bravo, Sir! Just remember to bring this up in residency interviews, and point out that the reason you "served" is to kiss up to those deans and impress your residency interviewers and how it shows a real commitment to yourself that less selfish people lack.
Now, are you sure you want to do medicine and not something to really help people, like derm? Or maybe radiology, because you "love technology" (and golfing). But if you must stick with medicine, I suggest allergy or maybe interventional cardiology, as that's where the money is. The hours suck, but by the time your realize that it will be too late.