Thus far, buying yogurt has proved to be one of the big sticking points in reducing waste. I haven't yet found yogurt in a reusable container, and NYC doesn't recycle any plastic besides bottles.*
I started eating yogurt a lot last year - who knew I could really love it when you get rid of all that fake sugar and flavoring? Anyway. Nothing beats yogurt and granola for a quick, simple breakfast.
I buy a big container from a dairy at the Greenmarket every week or two. They started to stack up on my shelf because I figured I would find a place that would take them, i.e. the Gimme 5 program. That hasn't happened, although I will take some home at Christmas (my parents' county recycles all numbers).
In the meantime, though, I've been using them as bulk-buy containers. They're lightweight and stack together, which means they're easy to carry, and when I get home I just wash them. I've even used them to store some foods that don't spoil fast and that I eat fairly quickly, like oats, brown rice, and pasta. I sharpie the food, cost, and tare onto the lid to make life easier on the volunteers at 4th Street Food CoOp.