Do you mean, how will go through the mechanics of picking 'em, when the time comes? You'll simply be offered a choice, like you are about weapons skills to upgrade.
If you mean which high level skills to choose, you might want to start a separate thread for that. Everybody will have an opinion, and we've had some animated discussions about it in the past.
To the Righteous belong the fruits of violent victory. The rest of us will have to settle for warm friends, warm lovers, and a wink from a quietly supportive universe.
