CentOS provides you with an upgrade path about every 18 months and Full support 5 years (with 7 years of support for everything but hardware drivers). so by the Time CentOS5 is out of support (2014) I will have the options to upgrade to CentOS 6(2008), 7(2010), 8(2011), 9(2012), and maybe 10(2014).
ROFL! Hilarious, if you dared to apply the same standard on CentOS you put on Windows, CentOS would be "unsupported" from the very beginning. All they are is a rip off of Red Hat anyway, doesn't take much engineering to burn a cd of someone else's work, yet again we see this is what you apparently look up to.