Well, spanish lock like the most reasonable for learn it, after english is the more preferred language (or chinese, youre free), so many countries speak it and spanish language people look like dont want learn forening idioms even if there inside their country.
On the other hand, spanish countries are cheap to visit ;->
AlfaFranek
Well, I will not tell any langauge to learn and why, instead I will tell you shouldn't learn polish.
1. It's full exception from rules your, that your head can get weary at least
2. Grammar is tough, has 7 cases for verbs, building sentence is quite loose etc.
3. Most poles already know english pretty well, meaning you don't even need polish to have conversation.
SilentSarey
I always thought Polish was a beautiful language, and I do acknowledge the many cases that it has. However, i don't find that particularly foreign, considering it's the same with Czech and Russian. But if most poles know English, I suppose that's a proper justification) but I don't believe the language will be going anywhere soon, however