Cleaned up my bash commpletion for ssh some, figured I'd put it up so can people can show me what they have that's better ;-)
SSH_COMPLETE=( $(cat ~/.ssh/known_hosts | \
cut -f 1 -d ' ' | \
sed -e s/,.*//g | \
uniq | \
egrep -v [0123456789]) )
complete -o default -W "${SSH_COMPLETE[*]}" ssh
You can drop the final egrep -v [0123456789] if you regularly ssh to ip addresses =)