Discuss amongst yourselves
I submit that 1997-98 was the best year ever for genre/ geek TV.
Season 2 of Buffy, the traditional choice for best season of that show.
Season 5 of X-Files, the last great season of that show before it all went to hell.
Season 6 of Deep Space 9, which I think was the best single season of any Star Trek show, ever.
and Season 5 of Babylon 5, the denouement of one of the finest SF shows ever.
In the background, Hercules, Xena, Stargate SG-1 Voyager (ugh), and Highlander were on the air as well.
1996-97 had the same shows on the air except for Stargate, with strong seasons of X-Files, DS9, and B5, but only half a season of Buffy-- and Season 4 of Lois and Clark, which saddles the year with demerits.
If you just go by shows on the air, there's something special about 2000-1, when Buffy, Angel, Farscape, X-Files, and the good season of Dark Angel were all on the air, along with Voyager (ugh) and Xena in the background. But it was Season 8 of X-Files, which stank up the joint beyond redemption. The following year added Alias and Enterprise, but: Season 9 of X-Files, and Dark Angel went from good to... not good.
There are people who think that Battlestar Galactica is so much superior to any other SF show in history that we're currently living in the golden age. But BSG's time on the air has corresponded with, er, Smallville?
Update: Yes, I forgot about Veronica Mars and Lost, neither of which I've seen but both of which seem to count in favor of the BSG era.
No, I didn't forget about Charmed for any of the eras; I only tried to.