I would like to set up an exercise in which students would need to submit their response to an assignment, and once they have done so they could see the responses of others in their class. We are using 1.9 for this semester and switching to 2.0 in the summer.
The new conditional activities feature in Moodle 2.0 will do this.
There are various third-party plugins for Moodle 1.9 to do the same (search on Activity locking) but if you are planning to upgrade in the near future, installing third-party plugins into your Moodle 1.9 will just cause you pain.