Which language class should I take?

This is another one of those it depends questions. What is your ultimate goal? If you plan to keep up with the language, and find a job with an international country, Chinese would be a good choice. If you are only fulfilling your graduation requirement, Spanish or Latin would be the most useful.

Chinese will probably be more rewarding. There are so many businesses and industries that deal with China these days, so a lot more doors will open up if you develop a serious understanding of the language. Plus I can use you more often to translate things.

Espanol.

Judging by you saying ”I have to take a language class to graduate” I get the feeling that you’re not really interested in foreign languages? So if you’re looking for the easiest class, I would probably suggest Spanish. Not that Spanish is the easiest language, but it’s the easiest class. There are so many outside resources for learning Spanish available to you in the U.S., it’s insane. Almost every film or book or TV show has a Spanish dub (Or at least subs). Spanish has gotten into our pop culture quite well, and you probably know more of it than you’d think.
Ignoring outside resources (Books, movies, etc.) I would really say that German is probably the easiest language to learn. At its base, English truly is a Germanic language. The everyday words you use are almost always cognates of words in German. People say that English is a Romance language, but the Romance is really just the icing on the tasty German cake.

If I misinterpreted your statement, then consider some cold numbers:
1) Mandarin (Chinese) is the most common language on Earth. If you’re looking to be able to speak to a large quantity of people, that’s your best choice.
2) Consider that German is a primary language in Germany, Austria, Switzerland, and Luxembourg. If you consider the nominal GDP per capita, Germany is a very important business language. It is also the second most common language after English in the European Union.
3) Spanish is the official language of 20 countries. If you want to be able to go to many different places and speak to people there, Spanish is a good choice.

While I personally disagree with the opinion, I can’t help but notice that if anybody says that any language is sexy, they pick French. That may sway you as well.

I agree with @Sarcasm that you should take Spanish if you’re just looking to earn the credits. There’s no way that learning some Spanish (and how the language works gramatically) can be bad for you (or anyone). Mandarin could be better if you plan on going into serious international business, but if not, Spanish will serve you well right here at home.

I took Latin throughout high school and college. I LOVED it. It was very challenging, however. I found it difficult but sort-of like a puzzle.
I took it b/c I was interested in philosophy, law school and languages, in general. It was a good choice for me.
If these things do not interest you, I wouldn’t recommend Latin. Spanish or Japanese would most likely be the most useful choices.

I agree with @jenandcolin about Latin being a good choice. I do disagree with it’s lack of usefulness, however. Latin is extremely useful no matter what. It will help you in all subjects. It is the basis for many languages, and many of the words used today are closely based on Latin, with many in use today being words being exactly the same. It will also translate into other subjects because of the orderly ways used to form different parts of speech and usages within them. I also agree with the other answers about the usefulness of the other languages that are used today, especially Spanish.