On a side note, I would also warn you against syncing all your contexts to iCal. You'll be faced with one long list of all your tasks in iCal.
I use BusyCal which allows me to see tasks on the calendar itself as well as in the task sidebar.
The only things I have in BusyCal/iCal are my appointments and tasks that really have a due date. Most often, they are bills such as "Pay my cellphone bill".
I only sync one context called "Critical Now". These are tasks that have to be done on a particular date. I created a Single Action project called "Bills." Then I would start to enter bill due dates such as
Power bill - March 18
Cellphone bill - March 22
Water bill - March 25
I usually set the start date approximately 7 days before the due date. This will let me see the bill in my OmniFocus Nex Actions perspective about a week before the due date. This is a subtle reminder that says I got a bill to pay by next week.
Then I set the due date for each task. Next, i set the context to "Critical Now". I'll go to preferences and map "Critical Now" to a calendar called "Bills" in iCal/BusyCal.
When I click on the sync to iCal calendar, OmniFocus will populate iCal with any tasks labelled as "Critical Now."
Once upon a time, i also thought that I should "schedule" tasks into a certain time. I never really got that to work. Nowadays, I would just create an appointment at a time of my choice (and sometimes not my choice either) and just label it with a project name such as this:
Thursday 3:00 pm - 4:30 pm - "Work on Powerpoint Presentation"
Then I'd refer to my "work on Powerpoint presentation" project in OmniFocus. I don't really care about mapping all the tasks in the Powerpoint presentation project. All I need to know is that I reserved that time block for this particular project.
I also thought it would be cool to see my tasks on a calendar. Even if it didn't have a real due date. When I tried to sync all my tasks over to iCal, I was immediately discouraged. My task list was so long. I didn't even want to look at it.
OmniFocus is much better at task management. It has the capability of filtering out blocked actions and only letting me see available Next Actions. Or I can go to a project perspective and just see tasks for a particular project.
The calendar is better at time management - when you need to keep appointments and time sensitive tasks such as bill payment due dates.
So take care that you don't sync tasks that don't belong in a calendar. Just because you can sync all your OmniFocus tasks over to iCal, it doesn't mean that you should...