Thanks to Leonard Nimoy’s presence as Spock, and his care in developing the role and working with the writing staff to keep him consistent, Vulcans were the first alien race to develop defining cultures in the Star Trek universe. This kind of thought helped create both a believable alien culture and an individual character standing apart from it, a race well worth studying as an example when creating a setting and a character to look at when choosing to play something you will define.
Vulcans have a well-developed philosophy, a sense of history and glimpses of a rich culture, as well as a reason to befriend humanity and join them in their adventures. The individual role of Spock goes a long way to define Vulcan culture, but also stands in contrast to much of it. Other Vulcan characters, like his father Sarek, Xon in the abortive Phase II, Saavik in the films and T’Pol on Enterprise, defined themselves partially by difference as well as his example. Playing a Vulcan without making it a caricature can be a challenge, but the depth of the society and portrayals to follow can really help. Some features created for the sake of drama fit awkwardly (see Amok Time for an obvious example) but all in all Vulcans presented a culture and an ethos I could believe, and Spock himself contrasted with it as he did with humanity, bringing the wisdom of the outsider to both sides.