Containers, of course! Tupperware has been around since the beginning of time, it seems, and it is very convenient. Especially for those of us with kids, who wants to risk broken glass? But, I'm here to tell you I've been using glass containers for several years, and the only person who has broken any of them is me.
I won't say "never" to plastic, since it is really handy. My rule of thumb is any food that isn't hot and isn't going to be hot - like leftover salad or cut up fruit - can go into a plastic container. Putting hot food in a plastic container or heating it up in the microwave can release chemicals from the plastic into your food. Of course, not all chemicals are bad, but we know that some are (see my video on Endocrine Disruptors: https://www.youtube.com/watch?v=WRbDhIY-xJ8). So, it's not a matter of being paranoid, but being careful. Also you want to check the integrity of your plastic containers. As soon as you see any cracks or evidence of wear, it's time to get rid of them (hopefully they can be recycled).
There are so many options for glass containers these days, so shop around for something that meets your needs. They can be expensive, so replacing your plastic containers with glass over time might be a more realistic approach. Make sure to look for something with a well-securing lid - that is my biggest complaint with some of my glass containers (especially if you are taking leftovers to work/school). If you are concerned that your container still has a plastic lid, you are not alone. The best approach to dealing with those is make sure your food (while it's still hot), does not make contact with the lid. Obviously if you have your container in your lunch box, it may get tossed around, but as long as the food is cold, touching plastic should be ok.
You'll notice I have some metal containers in the picture as well. These can be great too, and less expensive than glass. Be sure to avoid acidic foods, as those foods can interact with certain metals causing leaching of the metal into your food.
Finally I've got glass jars for storing dry goods like nuts, beans, popcorn kernels, etc. The benefit of these jars is to reduce reliance on the hard plastic containers these items might come in. While those containers can be recycled, they still use a lot of fossil fuels when they are produced and then again when they are recycled.
Over the course of the past 10 years or more, I have be working on developing more sustainable practices at home to reduce waste (including recycling). I have also been on a mission to swap out cleaning and personal care products with safer versions (products that limit exposure to environmental toxins).