There is a lot of tools to apt-get after deploying a new Debian machine, but you'll mostly add them while you go. For a laptop, you'll want to install some networking tools before you need them: resolvconf, dnsmasq, wpasupplicant, bluez-utils, irda-utils, mtr, iptraf, tcpdump

Also some offline tools unless you keep a package archive with you on the go: dict, what have you

linux