Java is quite nice. It reminds me of programming for Acorn RISC OS, which uses a very similar event handler model. Here are a few test programs I put together:
I've written more C code than any other language. This includes desktop applications for Acorn RISC OS, and portable command line applications, including my financial modelling code, for linux. Initially I used C because the "struct" support allowed me to manipulate complex numbers for generating fractals and other graphics representing dynamical systems.
I initially learned Perl from other peoples' code, in a blind panic, over one weekend. The following week I decided I liked it and moved on to these sources:
One of the reasons I like Perl is that it has such a short development cycle. There's (effectively) no compiler; you save your code, which is just a text file, and you run it. The systems tells you the line number if there's an error. It's like command-line BASIC in that regard. Another reason I like perl is that I can write substantial perl programs on my Sharp Zaurus C860 handheld computer, so I can program on the bus, on the subway, even while standing in line at the post office.
Perl is where I learned Object Oriented Programming (OOP)
Now I'm working primarily in C++, so here are some references I've found useful: