Decanter sets. I bought 2 at antique stores a few years ago--mid century glass is something I love. Then my grandma gave me all theirs, so now I have 9 decanter sets, from the 40's, 50's, 60's and 70's.
I have the set my grandpa used the most, with the case with a sliding door--I actually remember him using it. The glass he used most --you can actually tell. It means a lot to me to have that set.
I'll probably buy more through the years. I can't see myself not buying any that catch my eye. Most of my sets have 4-6 glasses. One set is missing a glass--my mom remembers breaking the glass when she was little, so that's kind of cool, too.
This is a decanter set: