i only went to a 3 month exchange. a semester will be better if you actually wanna learn the language. Although the idea of one year sounds really good, sometimes people do get really home sick towards the end and sometimes they even get sick of the country.
but it's a really really good experience! i reckon 6 months will be perfect
i'm going on student exchange to canada for 2nd semester of this year..
though it won't fit in exactly during out seconds semester. i'll be going during sept and dec for 4 months.. i only opted for 1 semester because of how i've planned my degree.. but if i like it i'm going to extend it...
you can also go and do winter or summer classes on exchange. what was recommended to me was that after my semester on excahnge to canada, i should go over to mexico for a couple of weeks and do a summer unit! which i'm considering so, if my budget lets me...