I'd bring antipasto and cheese.

Or veggies, pita chips, and hummus.

Grapes.

Trail mix

My boss always brings oranges and apples to share with me. Oranges are especially good because they don't require too much cutting.

black bean & corn salsa.

Can black beans, rinsed & drained.
Can corn, rinsed & drained.
Finely diced sweet onion
Can of diced tomatoes, drained.
Small can diced chiles.
Handful of diced fresh cilantro.
Toss, season to taste with salt, pepper, granulated garlic. Chill.
Serve with chips.

Has the advantage of being "vegan" without being frou-frou; low allergy profile. :-p

Fruit salad.
Baby carrots & hummus.

One of my favorite potluck items stolen from a coworker at my current place of work is called Texas Caviar - sort of like the corn and bean thing above, but with a sugar and vinegar mixture for a tang sort of like a three-bean salad. She usually brings it with Fritos, but it's good with any healthy tortilla chip too. I don't have the recipe with me at work, but I could find it at home - it's YUMMY and addictive. :) Hmmm. Now I might have to make some...

Depends on how many co-workers I had, and how much I liked them. :-D I love chicken breast strips marinated in something truly yummy like teriyaki or orange sauce, and skewered to grill. Even reheated in the nuker, they're usually pretty good.

The hummus sounds delish, too.

Veggie tray, fruit salad, broccoli/raisin/walnut salad.

For myself, I like apples and peanut butter. If you're making something for other people...the hummus and veggie tray always goes over well in my office.