Don't be an RA with the mindset that it will help with interviews or boost your resume. Be an RA b/c you've weighed your options and you want to do it. Although, I guess everything outside of class is a resume booster 😛. I did a few activities because I wanted more "filler" and it sucked...stick to what you like doing. Best of luck~~
EDIT: Oh yea, I was an RA too. I would totally do it again 😀. Then again, my school was pretty relaxed 😉, so it depends what the atmosphere is like for your program.