I only copied the binary because I do *not* want my normal nc to have the capability to bind to root-only ports.
> In many scenarios you probably will end up using something like capsh or pam-cap.
libpam-cap is probably easier for you:
apt-get install libpam-cap
pam-auth-update (enable "capabilities management")
# add "cap_net_bind_service cyberax"
It should be rather similar for other distributions.
Then start a new shell as your user (*not* via sudo "su - cyberax", use sudo -u cyberax, or su - cyberax from *your* user or such, pam_rootok makes a pretty unfortunate shortcut there) and voila:
andres@alap2:~$ sudo -u andres nc -l 434