Statement from ABC World News anchor Charlie Gibson:

Tim projected vitality — always excited about the stories he covered and intrigued by the people he interviewed. That's what made him so good, and his passing so hard to absorb. His competitors — just like his co-workers — held Tim in the highest of regard.

No one could see Tim in a room and not smile.

He brought so much joy and curiosity and sheer vitality to all our lives. As a journalist, he would set out like a great explorer. You couldn't wait to see what he discovered every day in the new world.

He was a defining American newsman. Love of country, love of family poured through him — onto the screen, into the work, into stories at dinner, into the little chuckle that reminded us — aren't we lucky to be here in this big life.

Tim Russert was a great competitor and a good friend. I am obviously shocked and dismayed by this news and extend my thoughts and prayers to his son Luke — he was so proud of you — to his wife Maureen and to the rest of his family; especially his beloved father. Tim and I worked together on Catholic causes, and I will greatly miss him.