I have my own desk and personal area behind it to stash whatever stuff I want. I kind of moved in.

I keep a tote bag with of a set of clothes in case I forget something someday. I keep a comb, toothbrush/toothpaste, extra set of eyeglasses/contacts. A washcloth and hand towel.
I run a mile on my 1/2 hr break so I keep a set of shoes here for that.

I bring my lunch most day and I also have a good food stash here. Aside from condiments and bread in the fridge/freezer I have non-perishables stashed here: a few cans of Progresso soup (in case I forget lunch sometimes), a package of fig bars, clif bars, tuna packs. I have powdered drink mixes (ice tea, gatorade, hot chocolate) and tea bags.

Also have dishes like my coffee mug, a giant mug good for heating soups, plate and utensils.