pull the other one. I (as well as many) work in an office environment...besides the infintecimal chance of being attacked at your computer, lets break your answers down tough-girl:
paper clips - ? no reply. 0 damage.
stapler - for throwing or hold it in your hand while punching.
CDs - like a ninja?
CD jewel cases - 0 damage.
cards - see 'ninja'
paper - mean paper cuts..ouchie!
0.5m steel engineers ruler [nice stick!] - it may give someone pause when struck accross the knuckles.
misc pens and pencils - kubotans etc - yep, if you have the time...how long does it take you to find a pen when someone says "take this number down..."
computer - mouse for a flail, keyboard as a stick phone
lots of product catalogues & books
- if you consider those as better weapons than your fists then I ask you, what have you been training for?
water glasses & coffee cups - more projectiles.
are you basing your office protection on cubicle seige warfare or self-defense? projectiles are a non-issue in the office unless a female co-worker gets angry with a male peer who she's slept with.