Western Slavic Languages

Most of us know that this includes Serbian, Croatian, Slovenian, and Bosnian. I know that S/C/B are very closely related, but the question is how related are they? Are they close enough that if I learned one would I understand the other ones rather well, or are they just mutually intelligible, and learning one would get me by in the other countries? If so, which one would be the best to learn. In an example, they say that Norwegian is the middle language, it shares vocabulary with Danish, but phonology with Swedish. How is it with West Slavic languages? I'd like to know, because learning one seems pretty attractive if it's 3 for 1.

Well, they hate the Turks as well, but the Turks left Islam with the Bosnians which made them kind of.. Turkish in their minds too.  The Croatians are an entirely different problem; Serbs tend to be East Orthodox and Croatians are Catholic.  Yeah, you've got far back historical feuding going on there as well, but these wounds are a lot more recent with the Ustaše and Jasenovac...  Croats, Bosnians and Serbians tend to be all deeply nationalistic (despite being the exact same peoples really, but don't tell them that) and easy to anger.  When they don't have something like WW2 or Eurovision to unite them, they're constantly taking pot shots at each other.

Seriously, it's a world of shit.  Half my family are Serbs, and I love em but... they're deeply flawed.