I recently purchased a new cymbal that has turned out to be so versatile that I have to post about it. I bought an 18" Zildjian K Dark Thin Crash to be used as the only cymbal (along with hi-hat) on a Mini-Cocktail kit I put together (more about the kit later). This cymbal comes in 16" - 20" sizes, and I think the 17" and 18" sizes are ideal for Cocktail applications.
Played near the edge, this cymbal has a good ride sound with some wash to it. Played closer to the bell, the ride sound loses some of the wash and becomes more defined. The bell itself has an amazing ping that can really cut through. As a crash, the 18" size is perhaps a bit too large (low pitched) to be ideal for a Cocktail kit, but it is a good crash with controlled sustain that tapers off fairly quickly. Also, it transitions nicely from ride patterns to crash and back to ride. So, this one cymbal can function as multiple ride types and as a crash cymbal. I would assume that the 17" size would work very well in this same situation. I own a bunch of Zildjians, and this is one of the best, most versatile cymbals I have ever played. Very highly recommended!