I am completely new to Mac programming. What should know / learn / choose etc.?

I seriously want to do some Mac programming and I have really read a lot about it but still, I don't know what exactly I should start with.

Which language has the brightest future, which one should I learn?

I thought about Cocoa - as far as I know that's what I should head for - but first, I should know Objective-C, but to learn Objective-C, I need to know C. Am I right?

However, almost everybody says that you should learn C++ instead of C because it's just an 'evolved version' of C but I had a look at some tutorials and they are really not the same.

Could you please help me, step by step? Thanks a lot!