Serious Eats - seriouseats.com

There are some great suggestions above. I might add that I've found one of the best and most inexpensive containers for soup or V8 (instant veggies) to be a recycled jar. I've used salsa jars, jam jars, and canning jars. Any of them with a good lid work...and if you need them to be, they're microwaveable. And dishwasher safe...and unlike some of the ziploc containers, they don't discolor with use.

Another great salad I like because it retains its crunch and gets better with time is a take on broccoli slaw. Mix a bag of packaged slaw with a can of mandarin oranges, a small bag of slivered almonds and some chopped green onions. Toss with Newman's Own light ginger sesame dressing. It'll hold in a container at your desk...though I try to keep it in the fridge.

And finally, never underestimate the importance of cheese sticks/string cheese and almonds. I like the Trader Joe's lightly salted variety.