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I have tried most of the major distributions in the last 8 years but I always come back to debian for servers. My major reason for this is that any distribution where the vendor wants to make money from sales will always need to be upgraded by reinstalling their 'new version'. This is normally a nightmare and the best way is normally for format the drive and install the new version. With debian you are constantly upgrading everytime you do apt-get dist-upgrade! Ok, so the install for Fedora might look nicer and it might be better for a desktop but once debian is installed you probably won't need to reinstall for years.
They have a new installer which is easier to use:
http://www.debian.org/CD/netinst/Check
http://distrowatch.com/ Debian is number 5 on the list but the top 4 are desktop driven distros. I haven't used FreeBSD for years. It is probably slightly more stable but you must trade some ease of use to get this - BSD tools v GNU tools are also hard to go back to! (eg. ls -h is gone)