Let me try to answer some of these.
I don’t use windows at work (where i do most of my development), so i don’t not know to best learn assembly in it. I’m pretty sure there is a way to do it however. If you are taking it in class, then just follow their method of teaching. Why do you need to know assembly? To be a m4D h4X0r?? 
I have not seen F# actually being used anywhere. I had to look it up just to remember what it was. I don’t know how good of a chance it has to become more common. I’m not a fan of an idea where compiler “knows” what language you’re using. You have to know yourself which language to use given problem at hand.
This i can discuss at great lengths :). First about Java. I’m not a fan of Java whatsoever, however like you said it is very popular. There are many huge commercial software packages available out there developed entirely in Java. I can show you some examples if you are interested. Java is absolutely everywhere right now and it looks like it will stay around for a long long time (someone has to support all this crap). This popularity however comes at a huge cost. Right now hardware is so fast and forgiving that even the worst developed Java implementations are usually good enough for what they are designed. However when you look at the actual quality of Java code, it is typically below the quality of the same code done in C-languages. I see this everyday at many different places.
At the same time, being a Java developer (or at least saying that you know Java) will open up many opportunities when looking for entry level jobs. I used to do entry level developer interviews and knowing Java or C# was the first skill quality i checked (i was told to do that ).
Finally about the salary. Salary range for entry level developer jobs depends primarily on the industry. For example, in financial industry in NYC (where i work) it is very much possible to get entry level position paying 55K-65K (70K is kinda pushing it right now). If you go in other fields like medicine or engineering (in general) you will probably get similar salary ranges. Obviously most of the “research” and most “government” positions will get you less. Also, NYC is very different compare to other locations. In finance industry it is by far the best location to look for a high paying job. Even when comparing positions in Jersey or Long island you can see how much more you get in NY.
At the end my recommendation would be to first figure out what industry you would like to work in and then see which specific skills you would need to learn to work in it.
From my personal experience working in consulting. You need to master one of: Java or C/C++/C# , two of scripting languages: Perl, Tcl, Python, etc and of course shell programming. That would be a good start.