Student Exchange Programs

i am wondering what is better- would i do more good by being a foreign exchange student or staying home, getting a job; using public transportation and volunteering in the hispanic community; i figure i could get fluent in Spanish and use greener transportation instead of just driving my self around. My friends say I should go because my parents can afford it and I will be more rounded. What does more rounded mean anyway? It seems like the kids who have gone just turn into big snobs and brag- they dont seem to care about those around them- just trying to make an impression all the time.