When creating a defect report, the title can be very important as it is sometimes the only part of a defect the developer will genuinely process. Not only that, but in Quality Center, the title of a defect is what gets emailed around. In his book, How We Test Software at Microsoft, Alan Page has some pointers regarding what to title a defect report.
He reiterates the importance of a good title and says that, when scanned as a list, bug titles can form an overall picture of a systems defects. Some of the particulars in creating a good title include limiting the number characters to about 80. That’s a little more than half of what you get in Twitter. Apart from that you need to walk the fine line of being descriptive, but not overly descriptive.
His example of a good bug title is, “Program crash in settings dialog box under low-memory conditions.”
The description is for any notes that don’t fit in the title. So, if you are including actual and expected behavior, that would go in the description and not the title.