This may be very obvious but...
Recently with the Apache exploits i have seen people getting rooted because they install and run Apache as root. I thought that it was just wierd until i read about an article on securityfocus.com that stated the same-so i figured i would help out some of the people new to unix.
always install the server software like apache, ftp, cups, whatever as a seperate username ie user: apache. if you install it as root and you get exploited through apache then the attacker has control of your entire system as opposed to just apache.
hope this helps.