Performance Danes  
Agility Danes (bios on dozens of Danes)
Morgan "Danger" Powers (top agility Dane)

Health, Training and Behavior:
The Great Dane Health Foundation
Dane Health Links by Ginnie
Lyn Richard's Dane Training Page
Dog Health Issues by DogLogic

Rescues:
Dane Outreach
Great Dane Rescues, Inc.
Great Dane Foundation

"Good" Dane Breeders: (the breeders listed are long established breeders who show their Danes and have a demonstrated commitment to the breed. Many I know personally.

Blue and Black
Colra Great Danes
Valinor Great Danes  
Kennel Kappadane
Amador Great Danes
Blue Moon Great Danes
WYSIWYG Danes
Tanglewood Great Danes
Cheshire Great Danes

Other Colors
Daynakin Great Danes  
Paquestone Great Danes  

Comprehensive List of Dane Breeders: Great Danes Online

Ear Cropping Information
The Great Dane Illustrated Standard - Ears
Stop the Crops
Thoughtful Discussion - VetCentric
The Australian View

Raw Food Diet Information
BarfWorld (Dr Ian Billinghurst)
Essential Reading (books)
Pictures of raw food ingredients
Newcomers FAQ