Must Have Tools:
Metasploit
Nessus
nmap
htop
less
cat
gPg
more
Openssh
wireless-tools
iputils
wget
tcpdump
dsniff
air-crack
kismet
bash
pine
rdiff
rsync
grsync
nfs
cifs
MC
vi
btaudit
screen
iptables
-------------------

Office & Extras:

Dates
claws-mail
MaemoMapper
pdf reader
Gnumeric
SciTE
Mirage
Mplayer
Media Streamer
Camera
fmradio
Gaim
Xchat
simple launcher
----------------

System:
Load Applet
IP Home
xlock
xterm
vpnc & vpncGUI
Canoe
config editor
DiskUsage
rdesktop
VNC Client & Server
MaemoFTP
QuickSynergy

I think that sums it all....

And yes I do use my N800 for work.