essential service (CentOS 5.5)

anacron	like cron daemon
avahi-daemon	for samba server
cpuspeed	monitor cpu
crond	task scheduling
haldaemon	auto detect new equipment
irqbalance	distribute irq among the multi-processor
kuzdu	auto detect new hardware
lvm2-monitor	maybe need to use for lvm
messagebus	use for shareing message among the process
microcode-ctl	update microcode whenever booting
network	enable network device
readahead_early	caching system for application
smartd	self monitoring system
sshd
syslog
vmware-tools