Whilst debugging something Cerebral Cortex using the excellent Zend Studio debugger, I found a possibly new nice feature.
When in a function/method you can mouseover any of the arguments to see what value was passed in for the argument.
Unfortunately, its a serialized version, but if you know what you are doing you can decipher it without an issue. Of course, if you don’t like the serialiazed version just check out the Variables tab in the Debug Window.
Here is a screenshot: