Tapping the Vein are awesome -- Heather is one of my favorite vocalists in the genre, if not ever. She can go from little-girl coo to full-on scary scream in the course of a single song, and sound good no matter what she does.
Ian will tell you more about Scarling...he's a fan, IIRC.
I also heartily recommend Kidneythieves. Mediggy. If you're going to get Trickster, go ahead and get the Reprocess, I think (though I still haven't gotten it myself, yet).
I've had Hungry Lucy on my radar forever, looks like I need to check them out.
Jack Off Jill are industrial -- so of course mediggy.
I forget Rhea's Obsession and Darling Violetta, although I have albums by both of them.
Kittie and My Ruin head more into metal and nu-metal territory, IMHO.