Herschel Biggs is the narrator of the first few cases when Cole is on Patrol. Considering that the first time you meet Biggs, he makes it clear how he doesn't want to be Cole's friend, the fact that he grows to respect and like Cole and is eventually the one telling his story is kind of sweet. Especially after the ending of the game.
Not to mention the fact that Biggs, in a huge contrast to some other partners, is actually pretty willing to defend Cole from the start. He may be gruff to him, but is equally quick to call out others on being greater assholes to him. He dislikes him for being a gloryhound, but doesn't appreciate others kicking a man while he is down.
Dr. Carruthers meets up with Cole during an arson investigation after he's been demoted because of the adultery charge. He tells Cole that he pities his wife and kids but not him, but that Cole's such a good cop that he's willing to give him all the help he needs. You can see Cole appreciate the sentiment immensely.
Phelps asking war comrade Kelso if he forgives him for Okinawa. The response: Phelps never needed to ask, because he'd been forgiven anyway.
The conversation between Jack and Biggs in Cole's funeral:
Jack: Very neat, Curtis. Maybe I can't work it out... but Phelps can. He may be many things, but he is one of the best detectives the LAPD has ever had.
In Nicholson Electroplating a former detective who is noted as being very similar to Roy recognizes Cole from the papers as the detective who had an affair with a German woman, while Cole looks lost and regretful Herschel tells the former detective that Cole isn't that guy.
In "The Naked City", Roy Earle will mock Bekowsky and Rusty, causing Cole to speak up and tell Earle he could learn a thing from his former partners.
Biggs makes it clear that all the time investigating arson's has given him heavy emotional baggage, and he's perfectly content to just write off fires as accidents and be on his way. Then during the second case he breaks down and reveals he had also served in the marines, and had seen his own men burn alive. When Cole tells him the victims in their latest house were connected to the victims from the last case and goes to interview neighbours, Biggs silently remarks "I haven't done this in years" and finds his investigative spark again.
Cole calling Roy out when he insults Courtney Sheldon and suggests that he was just another junkie who OD'd. It's not just an Awesome Moment but is pretty heartwarming, considering that throughout their time in the war Courtney and Cole never got along, with the former repeatedly challenging the authority of the latter. Even after it's revealed that Courtney inadvertantly assisted in the Suburban Redevelopment Fund Cole still respects his intentions enough to defend him in death.