I currently run my dedicated server with W2003 installed on, but I thinking to move to Linux, I have no experieces with Linux yet so I don't know what distribution to use. I thinking about Debian and also about FreeBSD, it should be something what I can choose from on ThePlanet, but any suggestion is appreciated. The server will be Web server with apache, PHP, perl and MySQL installed + email server + firewall. The main feature must be stability + performance + security (especially against DDos). Thank you in advance.
Centos is gaining an enthusiastic following in the web hosting industry as it gains a deserved reputation for reliability. Most DC's now offer Centos as a build option. It's a modifed version of Red Hat Enterprise. Check out http://centos.org/
choosing OS only doesnt bring you stability + performance + security You will need tweak it for your purpose, optimize, update patch, make it secured... If you are not familiar with Linux server management, I would suggest you to go with fully managed servers (like LiquidWeb, ServInt, HTTPMe...) or hire a good admin to manage your un-managed box