Or Brooke

Do you even have to ask?! Yeah, I agree Luke has done a lot for her but he left and he's never coming back again. Brooke is right beside her, she's her best friend and I'm sure she'll never let Haley down. They are going to grow old together for sure and that means they both are going to do more than just enough for each other. Friendship like Braley's lasts forever!

At the beginning, she was a true bitch with them (the party at Dan's place where she read Haley's note) BUT she made up her mistakes by organising a date. Then, in season 3 she let them the appartment. She's Jamie godmother and she was always a perfect friend to Haley.
Peyton and Lucas did some good things but Peyton was not really supportive of Naley in season 3 when she blamed Haley for leaving. She still encouraged them in season 1 even though she just broke up with Nathan.
As for Lucas, he was not their biggest supporter that's true but after that he believed in them and supported them.