When I was a student and was young, and pretty, and smart, and everything I am not now I always used Origin for visualizing data.
Commercial programs however pretty inconvenient, have to buy them again and again, and let us face: most people do not use their extra functionality. So today I decided, I go back to gnuplot. Gnuplot (now it is already version 4.6) is a reasonably handy, always existed and will always exist. 99% of visualization needed for papers can be done easily, and formatting can be saved in macros. Oh, and it has an interface to Ruby and Python, while smaller calculations and data manipulation can be handled inside. What else need more?
The pleasant surprise today was that it also has a Windows installer, and can be installed without any problem.