As it has been said many times, getting back to normal and doing "business as usual" is what we all need to do. Doing anything other than that simply lends credence to the events of yesterday, and allows those cowardly bastards to win.
This country will never bend to terrorist threats, and we will pull ourselves up, dust ourselves off, and move on.
As I tell everyone that threatens me (jokingly of course), "If you hit me, you better kill me".
The biggest mistake these cowards made is they still left us able to stand, and retribution will be had and it will be sweet.