Spanish or Mandarin.

I'm starting Mandarin in two weeks so we could help each other out. :)
I've also been learning Spanish for a few years and I could help you out in that too.

Well when you think about it learning a new language 2 times a week will make it harder for you to learn it. Because you will not constantly be in touch with the new language. So  I would go with a language that is related to a language you know. And then you can still learn other languages. My godlike perception allows me to see that you have knowledge of the english language. So I would either go with French or German.

German
because its the most spoken native language in Europe and will be understood in Germany, Austra, Liechtenstein, large parts of Switzerland the Netherlands  and Luxembourg and some parts of France Belgium and Poland.  The most learned language in Europe is English followed by German (I'm also including eastern Europe)

And because German is related to English the basic vocabulary will be easy to learn.  And will help you quite a bit in learning the language.

Haus/house Maus/mouse habe/have Tanz/dance Finger/finger Butter/butter Knie/knee Fisch/fish Kinn/chin Arm/arm Haar/hair Nase/nose  Ohr/ear Griff/grip Vater/father Mutter/mother Bruder/brother Schwester/sister Onkel/uncle Heim/home Nacht/night Schatten/shadow Schnee/snow  etc etc etc etc.

Ich habe ein Haus/ I have a house


Also this!  Thanks homer!

French
More complicated words in the English language on the other hand  are more often derived from Latin and not German. Latin is dead and directly derived from latin are Spanish Portuguese and to a lesser extend French.  English also has alot of French vocabulary  and some people say English is sort of a mix of German/Dutch and French. So French in terms of how easy it is to learn the vocabulary is easier than Spanish and Portuguese.  Because its closer related to English than the other 2 languages. 

Another nice thing is that when you know English and French  Spanish will be quite easy to learn. And when you know Spanish you will most likely understand Portuguese even tho you might not be able to speak the language perfectly.  (Spanish and Portoguese are somewhere between 2 different languages and 2 dialects of the same language)

The biggest problem with French is the pronounciation compared to how someone writes the word.   Cháteau (meaning Castle in English. The ^ above the A shows that in the past there was a S behind the  A)  So again  Châteu is pronounced  "shut-oh."  etc.  French is harder to learn than Spanish.



P.S.
I myself am German thats why I mentioned so many similarities of German and English.  I learned English and that helped me a lot in learning French.  After I learned French I found it quite easy to learn Spanish because those 2 languages are related.  The vocabulary of French and English helped me learn the vocabulary of Spanish  and the Spanish pronounciation is quite similar to the German so thast also easy for me.

And btw the second language I learned was not French but Japanese. Its funny to see how many German words are in Japanese  and of course the number of English words is even higher. The problem here is that I forgot 99% of the Japanese I learned because you have noone to talk to.

Its always good to learn a language and than based on that learn another language.  Next I will learn polish because half of my family lives there and when I learned Polish I will it easier to learn Russian/Czech etc. 

So even tho I am German I would say  go with French when you plan on learning other languages after you "mastered" French.


EDIT:  Whhoops I just saw there is no FRENCH lol  so well then  Go for German! :)  And if you have no real interest in learning German def go for Spanish. Spanish  has the biggest number of native speakers in the world even before English (where not all people are located in the same place like China. No Chinatown doesnt count!)

So if you want to travel alot Spanish is a good choice.

German. Very much like English so it's easy to learn and it is the second most spoken language...on the net...

Russian. I took two years of it and I love it! And I have no Russian/East European background whatsoever, just took it because I'm interested in Russia and Russian history. It's pretty easy once you get a handle on the patterns and rules.

Japanese, as a gamer it would help out a lot.

japanese (to be able to play JP only games) or german (To gain the ability to yell "NEIN" like a native).

edit: Like some people already said, due to the similarities, german might be quite simple to learn. the only pain might be learning the german articles ~

The definite articles in German refer to specific persons, objects, ideas…etc. and they are : der, die, das, die (plural) they all mean the expression “the” in English, der is used for masculine nouns, die is used for feminine nouns, das is used for neuter nouns, and finally die used also for plural nouns.

( http://german.speak7.com/german_articles.htm )

funfact: pretty much every game console except for the Gamecube, N64, NES and SNES (if i recall correctly that is) do have the feminine article, "die". (Yes, its written as "to die") while the 4 Nintendo consoles mentioned have the masculine "der". (except for if you spell it out, the word "system" turns the nes and snes into neutral words, and are therefore not masculine anymore. :P) But yeah, in a nutshell nintendo is DA MAN (except for the wii, she's a her :P), while sony and microsoft only have girly machines.

I would say learn Japanese. It could be usefull for the future. I would stay away from Latin. I dont see the point in learning a dead language.

It's really hard for a westerner to learn japanese, korean or mandarin because it's a completely different way of thinking about things. So yeah, if I were you I'd take the challenge. Or maybe german. That's what I call a badass language. The language of anger, as the Rammstein singer would put it

For western languages I think portuguese and maybe the slavic languages are pretty hard too. A lot of people say that about the uralic ones, but personally I don't have issues with declension. Actually is kinda easy to learn parts of it when you know exactly the theory behind an ablative case, an ergative case etc.

Hmm.. I didn't know German was so close to English? I probably should've taken that instead of Spanish in high school. As far as my preferences goes, I've wanted to learn French, Mandarin or even Cantonese, and/or Japanese.