Quick access to frequently visited directories

Define hashes for directories you frequently cd to from the command line, and access them as ~hash_name.  For example, my .zshrc has:

hash -d fx=~/dload/app/comm/firefox
hash -d prog=~/d/prog
hash -d personal=~/d/personal

cd ~fx will take me to ~/dload/app/comm/firefox, cd ~prog will take me to ~/d/prog, and so on.