Rebel Blockade Runner, mostly because it's the first ship you really see in A New Hope and my first interaction with the Star Wars franchise as a kid in the early 90s.
That's how I think of it too, but apparently it's a CR-90 Corellian Corvette. I imagine that info was created later and didn't exist for the first movie.
Makes most sense that blockade runner is a description of the role it's being used for, same way you can describe any car as a taxi if that's how you're using it.