At that time, the hot technologies were Java, MySQL, Hibernate, and maybe Flash. I was at the University and I studied a bit too much of math (like 4 courses on Linear Algebra). I really wished I had studied more about compilers, and all sorts of programming paradigms, from Assembly to concatenative languages, to very high level languages like Haskell. Stretch your brain as much as you can while you're young. It's not so much about what things are useful, it's mostly about opening your mind as much as possible.