If you work in an office environment, chances are you've had your own cubicle at some point. Many of us will spend significant time in one of these partitioned workspaces as we undertake our corporate climb to the corner office.
In every desk at every cubicle, there should be a corporate emergency kit, otherwise know as “chocolate.” In case of emergency, open the chocolate drawer and indulge. If there's no immediate situation to deal with, then it's a perfect time for a drill. Have some chocolate anyway.
You'll need to replenish your supply quite often. The good news is that coworkers will often sell large chocolate bars on behalf of their children. The bad news is that this is not the most cost effective way to stock up. Try buying broken bars from a bulk bin. It feels a little like taking in strays. Have you ever wondered what the shelf life of chocolate was? Basically, it will last as long as the shelf, so you're only limited by space. You may find a deal at a big box store; some club packs of bars have trailer hitches on the side.
If you have access to sunlight, a live plant makes a nice homey decoration. Some people talk to their plants. If you don't have sunlight, try getting an artificial plant. And lie to it, because it's not real anyway.
If you don't want to be bothered by coworkers, simply put on a pair of headphones and you're now in “stealth” mode. This will inhibit people from starting conversations with you. If you sense someone approaching and believe they'll try to talk to you, just close your eyes and start punching the air above your head in time to the music. This “rocking out” will often solve the problem of being bothered by chatty coworkers.
If you have a pet, it's entirely appropriate to display a framed portrait of the little beast, for those moments when you don't have time to show off your wallet photos. Also, you'll need to remind your colleagues of when your pet's birthday is, to avoid the embarrassment of forgetting to get a gift. Post-it notes work wonders for these little reminders.
And finally, as for other knick-knacks, the workplace is the perfect environment to display the type of crafts made by related children in grade school art classes. It shows that no matter how esthetically unpleasing a piece of art is, you're happy to lovingly show it off at your place of business... If only to keep it out of the sanctuary of your home!