It's Giselle Loren. She also did the voices for two video games, one for the Xbox and one multiplatform. I think she does a good job but she really does not capture all the emotional nuances of the character the way Gellar did.
But, face it, Gellar is not coming back to Buffy, no way, no how. If we want new Buffy content we'll just have to get used to a new voice, and Loren's is better than most. Like we've seen, some people can't even tell the difference.
I don't interact with the Browncoats that much, except crossing paths in generalized Whedon-mania, but I do think their latest obsession leans more toward a second movie. I'm sure there are some on the fringe who want the show back, though.
Whedon fans seem to be prone to taking comfort in unrealistic optimism. Whether it's the resurrection of a favorite character, the continuation of a show the WB simply seemed to have it in for or the hope of revival of something long dead and buried, they want to believe. After all, Buffy did rise from the dead, both in a schlocky movie becomes a hit show way and a couple of times on the show.
My latest obsession is Doctor Horrible. I know, intellectualy, that in the real world it's small potatoes, but as a Whedon fan I'm amazed that people aren't running around in the streets proclaiming it the greatest thing ever.