I need to choose between those 4 OS for my VPS... CentOS, Fedora, Ubuntu, Gentoo, Debian help me, what to choose?
choose the OS you are familiar with the most. If none of them is familiar to you, I guess you have no experience to manage a server. In that case, you should hire someone to manage it for you, and he can choose what he knows
I'd go CentOS, but that's just out of personal preference. At the end of the day I think any of them would suit you well, just go with the one you're most comfortable with using.
I would go for Centos, it is Enterprise RedHat Open source. The good thing about this is support is long term unlike those eg Fedora.
I am a system admin since 1998.I used most of the Os. For Desktop and Server , i can guarantee gentoo is the fastest (min 3x faster ) Os on earth after correct configuring.But if you didn't use gentoo before you can choose debian or CentOS. Portage (gentoo's online package system) is the biggest selection on earth.(Debian after) and program/software installations are so easy (emerge unrar , you see it is easy ^^).The only thing is you need a good configuration especially kernel and make.conf.
If Slackware was a common option (it's what I'm most comfortable with), all my servers would be using that, but it's highly unusual for hosting companies to offer it. Go with whatever you're most familiar and comfortable with. Otherwise, I'd suggest CentOS. It is well supported and simple enough to manage. And the track-record isn't that bad.
depend on what control panel you want to run. usually we recommend the people use CentOs for cpanel.however,Fedora core also a great OS.while the rest aren't popular as in server default os.