The White Wolf games are early 90s, (Vampire is 91), so shortly after AD&D 2E was released and was still doing well.I'm not sure about that period, but the earlier period in which D&D wasn't doing all that well, the late 90s, was one of the most fertile and creative times in the history of rpgs, with many games released then which are still around in some form to this day: Deadlands, Seventh Sea, Legend of the Five Rings all the White Wolf games etc.
Deadlands - 1996 - within the period where TSR starts struggling
Seventh Sea - 1999 - within the period (but barely, because 2000 is 3E)
Legend of the Five Rings - 1997 - within the period (though I'm not sure how popular the RPG was, compared to the CCG).
Of those games, I tend to see the White Wolf ones as the big, important games which got a lot of people into roleplaying - but they were also at a time when D&D was with a new edition. (I was running games at university at the time, and I remember the buzz for Vampire, though I didn't play it). Vampire was very important as it reached a segment of the market that wasn't served well by the D&D of the era.
Cheers!