I'm looking for an anime that features an American foreign exchange student to japan. Does one exist? no idea.
Wasn't there one that was like Gens... G.. something. It's a school club and there's this American girl that supposedly only talks in anime quotes or something.
Ai Yori Aoshi has an American exchange student in its main cast.
Code Geass... hehehe. Totally counts, right?
Soul Eater
Love Hina sort-of-but-not-really has one. He's not really a student any more.
I can't think of many others at the moment, but I feel like there are more.
As for the spoilers discussion, I share MrWiggles's opinion on them as they apply to myself for the most part, but I can see how it detracts from the experience of others. When I was younger, I actually quite often spoiled things for my peers as I simply didn't understand at the time that it was poor etiquette to do so. Afterwards I didn't really understand the reasoning behind it, but I've come to acknowledge it.
I agree with MrWiggles that the story needs to hold up on its own, that it's about the entire story and not just about the big reveal at the end that needs to hold your attention. If story is completely worthless after being told the ending, then the story itself is completely poor.
That said, there is a certain enjoyment in being surprised by things, and of having your own guesses as to what the future might be and then told that you were not so clever as you thought. Case in point, I recently watched
The Girl Who Leapt Through Time and on numerous occasions I thought "I totally see where this is going. This is going to be important later, I just know it." Then the show proved to be better than that and kept me thinking. In the end, most of my predictions were wrong because it suddenly shifted from setting up a cliche to telling a good story. I thought that was quite clever, to encourage the audience to tunnel-vision the ending and then surprise them pleasantly. Of course, my experience probably isn't the only one, but I'm just saying that if it were spoiled to me, I wouldn't have been as happy with the outcome.
Similarly, not having a series spoiled gives you a lot more in rewatchability (if the media itself is worthy of a reread to begin with). If you finish a series and then reread from the beginning, often times you'll see something you missed: little details of no real importance but might be symbolic or foreshadowing when see them the second time. If the ending is spoiled, then one would be on the watch for hints at the end from the very start (and not having a very clear picture of the ending, this process is often clumsy and ends up in misinterpretations). This may go so far as one not really enjoying the media and instead trying to scrutinize everything, similar to watching a film when the viewer knows they are taking a memory test involving what they watch.
I've enjoyed quite a few series without them being spoiled, and I've enjoyed quite a few with them being spoiled. Some I definitely know I wouldn't have enjoyed as much if they had been spoiled, and others it didn't really matter. The best series, in my opinion, are those in which the story is very well made to keep the audience entertained as they skillfully manipulate the assumptions of the audience into creating their own surprise. Such series wouldn't be ruined by spoiling them, but doing so would rob the audience of the full experience. That, at least, should be respected.