When is confrontation worth it?

A lot of us make individual threads about specific situations at work (I've done it when a facility wouldn't pay for required training) and want to know whether to report X to our supervisors or not. And it seems like the advice we give/get is usually along the lines of 'try to handle it yourself and keep your head down to avoid blowback'.

I recently had a situation at work where someone above me was super-inappropriately gay-bashing on the floor in front of our residents (details are on my blog if you're curious). It got me thinking: what do most of us feel is worth reporting?

Would you report hate speech? From a peer or a supervisor? Med errors? Patient safety issues?

How far does someone have to go at your facility before you're going to "tell" on them?