Take a look at this image below:
That's a LOT of things a member can do.
Needless to say, most communities don't need any of these. For most communities, I'd remove document creation, blog posts, polls, events, ideas, videos, and anything else that distracts from creating discussions.
It's only once the discussions are going that you might want to consider adding new features. For now, it's a distraction.
Even better, why not gradually let members have access to more features the more they have participated? Create multiple access levels and enable new features at each new level.
This motivates members not only to participate in more discussions, but to actually use the new features they now have access to.