I heard memcache is the best, do you guys know anything else to install on a new dedicated server?
PHP & MySQL would be a start.
I mean, other than the essentials.
It all really comes down to preference. On all my servers I have flash-cache installed.
For mail, dovecot and postfix + roundcube.
I also have eAccelerator installed, which makes a huge difference performance wise (I even wrote a tutorial on it -
http://un-ruled.com/showthread.php?tid=464807 ).
PHP-FPM instead of the standard mod_php (if you're using apache). Also, the obvious things such as
chkrootkit,
BFD,
APF and maybe ClamAV.
as long as you dont install suPHP and suHosin, then you can use the cache systems with PHP. Its one or the other in this case, can't have both cache and suPHP
edit: well you can have both, but cache wont be used if you do