Let's face it, Star Trek: The Next Generation was nothing without "Data"! And, similarly, Brent Spiner was nothing without ST:TNG! The only other show that I liked him in was as the terminally-down-on-his-luck hillbilly appearing on a few episodes of the "Night Court" series!
Most of the characters on the show were integral to its success, but there is no question Data was one of the most important. Like Spock before him, he was the detached observer of human behaviour. In a way, the entire seven year run of the show could be called "Data's Journey". The evolution of his character from "Encounter at Farpoint" to "All Good Things" is a remarkable testament to the skill of the writers of the show and of Brent Spiner's ability to crawl into the skin of his character.
To say that Brent Spiner is nothing without ST:TNG is endemic of very narrow view. He has been in blockbusters like "Independence Day", Academy Award nominated films like "The Aviator" and "I Am Sam" and critical successes like "Introducing Dorothy Dandridge".
Ok. We won't discuss "Master of Disguise". Even Pacino was in "Gigli", so every good actor can be in a turkey or two 
