Project Management - Top challenges

As major IT and security projects should have a project plan, these two lists represent revelant challenges that should be factored in:

Project Management - Top challenges
http://pmtips.net/project-managers-top-ten-challenges/
http://www.allpm.com/index.php?name=PNphpBB2&file=viewtopic&t=3574

QUOTE:

Top challenges identified by author (with discussion of 1st five)
1. Lack of PM involvement during the sales process
2. Unrealistic schedule expectations
3. Renegade team members
4. Financial management/budgeting
5. Resource availability
6. Communication
7. Scope management
8. Customer requirements definition
9. Over-involvement by customer team members (too many cooks in the kitchen concept)
10. Lack of knowledge transfer to delivery team (this is another sales process issue that concerns me)

From 2004 Article (these challenges still apply)
http://www.projectmanagementcourse.com/project-challenges.html

1. Unrealistic deadlines
2. Communication deficit
3. Scope changes
4. Resource competition
5. Uncertain dependencies
6. Failure to manage risk
7. Insufficient team skills
8. Lack of accountability
9. Customer and end-users are not engaged during the project
10. Vision and goals not well-defined