The cups at work are thin, waxy paper that have a 3 hour limit-a disaster on a desk. Another favorite is Chick-fil-A, when I can find one..they have diet doctor pepper and large styrofoam cups!
On a trip to Sea Island a couple of years ago, I loved their clear cups and talked one of the pool attendants into giving me a sleeve of them. I have a few left but I keep them in the back of my cabinet for emergency use.
One of my favorite gifts I ever received was from Meg. When she got engaged, I helped her put her entire mailing list into Excel. The next time I went over for dinner at her house, she had a surprise for me, a box full of 100 styrofoam monogrammed cups. A perfect gift!! I loved them so much and have one left. This weekend, I went to Swoozie's in Jacksonville and they had the cups there. I think I need to order more even though I know styrofoam is horrible for the environment, but I really like it!