I bought an aluminum or stainless (don't remember which, now) water bottle to keep on my desk at work that I would refill from the water cooler. After a few months, when you removed the top to refill it, there was an unpleasant odor inside and the water developed an odd taste. I threw it away.

My plastic bottles just get a cycle through the dishwasher once in a while and all is good.

But I still refuse to drink coffee from a styrofoam cup.