Tools without which I would not be the same man
Obviously, there are a lot more tools that one uses during the day, especially the little ones we never think about (hello, grep and openssl). These are just the ones I consistently find myself installing when starting from clean slates.
Infrastructure
freebsd
nagios
zabbix
sysmon
scponly
duplicity
haproxy
mysql (+replication)
rsync
lftp
Development
vim
ctags
mercurial
git (+tig)
screen
selenium
firebug
Sequel Pro
phpmyadmin
VirtualBox
Management
Feng Office
Skype
DropBox
iWork ($)
graphviz
Security
tcpdump
ngrep
socat
ratproxy
nikto
skipfish
tor
Interestingly, the only not free one among these is iWork.