Tangibles: undergraduate degree (in anything!), a Master’s Degree from an ALA accredited institution:
Skills: Requirements vary depending on specific type of librarianship, but all librarians must be adept with ever-changing technology and the evolving information landscape.
Intangibles: intellectual curiosity, ability to embrace change, ability to work well with people, excellent communication skills, strong service ethic, some serious technology and critical thinking skills.
Academic (often these roles are combined, especially in smaller libraries)
A lot of academic librarians have faculty (professor) status, which means they are required to meet scholarship (usually publishing) and service expectations in addition to regular librarianship duties.
Public (often these roles are combined, especially in smaller libraries)
School
School Library/Media Specialist (most states require teaching certification in addition to MLS)
Special Libraries
Corporations, museums, hospitals, government organizations, media networks