Oh nice, a cool topic- thanks!
I like a number of characters, but for pure friendship... if I had to pick one it'd be Sam.
She's amazing in: looks, intelligence, personality, and even things like morals and courage.
One thing that would be interesting is discussion on spirituality. She doesn't seem to care for the supernatural, but in time- who knows.
2nd runner-up might be Jerry. Incredible life experiences, leadership, intelligence (w/old age quirks), courage, connections, etc.
Tied for 2nd?- Brittney or Alex. Or Clover. They have a lot of the same attributes as listed for Sam. It's really tough to choose.