Things you can do here:
1. Ask a Question
2. View ALL Questions
Your goal should be to rank for both and as many keywords as humanly possible. Sites that achieve real authority with Google rank for long tail keywords AND broad keywords. You should do whatever will provide the most value to your target market because that's what Google is looking for -- to provide quality resources/information to the searchers. So do that. Target broad keywords and long tail keywords within your web content and within the anchor text of your link building efforts.
When you win rankings for the broad keywords, you'll have great rankings for the long tails as well.