If you want a trusty stainless steel water bottle that is school- or office-friendly, then you'll like the S'well bottle. The S'well Blue Granite Bottle is BPA- and BPS-free and made with food-grade stainless steel. It uses S'well's "Therma swell technology," meaning it's triple-layer vacuum insulated to keep your water cold for up to 48 hours or hot for as long as 24 hours. This varies on the size of the bottle -- the bigger the bottle, the longer your beverage will maintain its temperature. There are plenty of bottle designs to choose from and sizes including 9, 17 and 25 ounces.
I liked that this water bottle is designed to be appropriate for just about any setting and it doesn't sweat. If you opt for the 25-ounce bottle, it's on the heavier side so if weight is a concern, choose one of the smaller options. Another downside to this bottle is that it is not dishwasher safe, so you will have to wash it by hand. This isn't the biggest deal if you mainly intend to use it for water rather than flavored or hot beverages. It also doesn't have a handle like many others on the list, so I wouldn't recommend it if you're going on a hike or walk.
If you're a student, an office worker, you attend yoga class regularly or have another reason to want a bottle that you can keep by your side, then the S'well bottle is a safe choice. You'll also be satisfied with how refreshing your water tastes throughout the day. When I tested it to see how cold the water remained over 24 hours, it fell short, but realistically, most people aren't looking to drink water left overnight. They will most likely refill their bottles daily. This bottle would make the ideal gift as well since it's available in many designs and shades.