Always usually? I don't think that's possible.
I'm all for libraries, but they're not worth much if the tomes are never opened.
And dude, fucking get Soulstorm. I really, really love it. It's got a much better single player tactical... campaign thingy than Dark Crusade, and the Sisters are actually a pretty decent faction for a game that's already done so much. They have trouble distinguishing themselves in the gameplay sense since so much has already been done, but the unique look and feel help, and they're still very solid and just different enough to be fun (plus you can scream at your computer about burning heretics and not feel quite as foolish about it).