This all depends upon your business rules. If your business requires realtime data (ie traffic officer pulling a warrant search for a traffic stop), you need to make sure your reporting server has the resources to respond as required. The complexity of the reports also plays into this equation. If your report is only pulling minimal information, the discussion may be a moot point. However, your CIO is trying to pull accounting history for the last year on your entire account tree, ouch (does she REALLY need it realtime?)!
We do run all of our reports realtime. However, it doesn't hurt since we are a small company and our database is only 50GB in size. Will this practice change in the future? NO. Our business rules require realtime reporting so we will have to do what is necessary on our part to make sure the application meets the business rule. There are reports that we are able to run in batch mode overnight as well. We don't have all of this well defined at this point but will in the near future.
All of this to say - define your business rules first. Unless something is absolutely critical to know realtime, obtain buy-in for a near realtime solution.