The most common operating system on VPS is Linux (with multiple distributions), Freebsd,windows server, and so on. In general, the VPS operating system is not free installation, Linux series VPS can install more than one Linux distribution, but can not install Windows, in contrast, the Windows series VPS can not be modified Linux. This is the first consideration in purchasing, according to your needs to determine what kind of VPS to buy
I strongly recommend the use of linux:linux high efficiency, low requirements for hardware configuration, high security, no need to run a graphical interface, you can freely streamline unnecessary functions, save the system resources used to run applications, rich and diverse network applications, some software does not have a Windows version, Or the Windows version is ineffective;
Linux distribution options: Linux has many different versions (distributions), used most Redhat series (representing Redhat, CentOS, Fedora) and Debian series (for Debian, Ubuntu), The main use of the VPS is CentOS, Ubuntu, and other common retrofit versions, such as Arch, openSUSE and so on. The difference between the different versions is not very good, it depends on which one you are familiar with, and which one you prefer. If you are a novice, it is recommended to use CentOS or Ubuntu, especially Ubuntu, and I am personally inclined to use CentOS 6 because I am more familiar with it.
Use a 32-bit or 64-bit operating system? Very responsible to tell you, do not hesitate to choose 32! Unless the following two scenarios: Your VPS memory far more than 4G, or you want to run a software can only run under 64 digits. Choose 32-bit reason: Run the same program, 32-bit memory small, the use of 32 VPS on the absolute majority of people, 64 and 32 some places have not the same, there are difficult problems, 32 more easily find information, find friends to help solve.