If you decide to do a voice pack I would make it as a separate download, or at least make it possible to download the game without the speech pack as they can really inflate file size.
Oh, the game is plenty big already without a voice pack
Voted in your poll...
IMHO, the game already appears that it will have plenty of pure unadultrated beauty and excitement without the need for speaking parts. I like when there is a character voice pack SOMETIMES in a game, but really only when it is done flawlessly
and the characters' voices are VERY accurately depicted (which is kinda subjective, I know) from their personalities (both things being very difficult to do). To be completely honest, I think most people are so eagerly anticipating the release of this game, and have been for so long, that the lack of a voice pack will not really affect the overall satisfaction. Everyone will just be so grateful to be able to finally play it!
That being said of course, releasing a "Heroine's Quest v. 1.1" later on in the future with said voice pack is also another route you could take. Ultimately though, I think everyone is pretty much going to tell you that this game is YOUR baby and therefore you have to do what feels right to YOU. No matter what you decide, people will stand behind your decision (do we have a choice? Ha.
) and be excited no matter when the game is ready for release. So, in the meantime, keep up the FANTASTIC work.
Edited to add: Oh brother. I think I was delirious from lack of sleep when I wrote this post. I'm sorry I was so long-winded, sheesh... :/