Think about the kind of work that accountants do and their role within the work place. That should help you shape your answer. To me, one of the most important personality characteristics for accountants would be having a good sense of logic. If they think logically they, they will be able to approach the accouting task in a manner that will best suit its successful and accurate completion. I see having patience is part of this picture as well. With patience, all of the calculations are checked; all of the data is collected and dealt with appropriately; no short-cuts are taken that could affect the accuracy of the final product. Most accounts are detail-oriented people who loved numbers and making it all work in the end -- like a perfect puzzle with every piece in the right place. Accounts need to be knowledgeable about current accounting practices within a company as well as from a legal standpoint, but they all need to be flexible thinkers who can approach and test a problem from a variety of angles or consider multiple opinions, but then decide on the best course of action or method for the given situation. As with any profession, there are lots of qualities that come together to make the most successful people rise to the top of that profession.
The two references below talk about personality traits and skills that are considered important in the work place. You may consider how those might be important in the account's job.