English and Spanish

Hard for me to tell whether Norwegian is hard to learn, given that I'm Norwegian

Though if you learn Norwegian or Swedish you will fully understand the other language as well, and likewise they will understand you. They are very similar. No need to learn both there.

English, Cantonese and Mandarin

Is it not a bit obvious? :D  if you can have a fluent conversation with the people from all the countries you learned the language, And by that I mean on the internet or in person

Interesting. Since they are so similar, it's a nice pick either way! 

Guess now I'll just have to decide wether to start with Swedish or Norwegian. 

Spanish is my native language.  I learned english a couple of years ago, and just recently learned portuguese.  

But my grammar is good only in spanish.

Just wanted to be sure. :)

And yeah, I can communicate pretty well with people from those countries. I have some friends in France and Italy, so this helps me practicing these languages. Portuguese and Spanish I use every single day, and English I use pretty often too (mostly here tho). But I'm yet to talk to a person from Greece, so there's that. :P

Spanish, english and learning japanese

Finnish, English, a bit of Swedish, and very, very rusty German that was never that great to begin with. I also have some clues about Japanese, but I wouldn't say I speak it. Not that I speak Swedish or German in practice either, but I should be able to should I refresh my skills.

French and English