ServerMatrix servers come all ready to go with apache, mysql, php all running.
Cpanel/WHM is required only for managing customers if you intend selling hosting accounts, although it would be recomended if you know little about server management. It depends on what your going to do with the server.
Whether or not you need any other options is again all dependant on what you are using the server for, can you post a bit more info.
i would say that cpanel makes running a server much easyer because it automates things for you like
i have been useing command line for a long time and found that cpanel makes life easyer and infact some of the imposible things "verey hard things to setup" can be easly installed or be done now thanks to it.
and the floodguard is a good addon against attcks
but you will need to manage and update things because SM want update every thing for you.
if you want a total managed server checkout theplanet.com
if you feal you can lurn stay with SM
but i recomand you install few more things like APF+antidos
also enableing cpanel security options
and install mailscanner + clam anti virus
you can also check out http://forums.servermatrix.com and see what you can find there.
I can do basic admin, but things like mod_security, installing mailscanner & clam may be things I don't want to spend time learning....
I saw someone advertising a service to install all the security features on your server for a reasonable price. Perhaps I can look into that. I am not yet ready to spend for a fully managed service like theplanet.
There are couple of services I tracked down on SM forum that can do security admin for about $25/month. Pros: they stay on the *leading edge* of things, I am sure. Cons: I would not know exactly how the server is config'ed (I guess good someone who does not want to tinker with the box).