The "waves" conceptualization of democratization model is still commonly used. In fact, people often talk about how we're in a rather depressing "fourth wave" right now (Otpor, the Color Revolutions, Arab Spring, perhaps Burma), though there's some debate about whether or not this is actually a wave.

But thinking of democratization as coming in "waves" where knowledge and inspiration diffuses through similar countries and circumstances is still common. But yes, the idea of a third wave that simultaneously covers the very different cases of Southern Europe, Latin America, and Eastern Europe is still very common (democratization in South Korea and Taiwan as well as in African states are ambiguously included--sometimes they're emphasized, sometimes they're forgotten). As far as I know, perhaps of the dominant ways of thinking about democratization temporarily and spatially.

There's less agreement on exact the causes for democratization and democratic consolidation (two different things), but even here Huntington's assessment is still influential.