Fast-forward to the present, Heidi (née Montag), 27, says the night that made "You know what you did" a household phrase is now water under the bridge.
"I've talked to [Lauren] a few times on the phone and we've caught up," Heidi told PEOPLE on Friday. "She's been really sweet. The last time we talked was like a year ago. I lost her number so I haven't been able to call her [recently]. I told her I got really caught up and I was sorry about how things happened. I told her I miss her and she told me she'd always be there for me."
Heidi, who wishes her ex-BFF a "blissful" engagement, acknowledges that the two won't necessarily always be "friends," but they'll "always have a special place" in each other's hearts.
"We've been through a lot and we have a relationship that only the two of us would understand," Heidi explains. "She was my best friend for a long time."
Spencer Makes Peace
The TV personality's husband, Spencer Pratt, also lost a dear friend while caught up in the mix of reality television.
"I turned on him for just being the nice guy that he is," Spencer, 30, told PEOPLE, of childhood pal Brody Jenner, who briefly dated nemesis Conrad. "I wish I'd handled that differently. I abandoned him and our friendship and we were such best friends. I got caught up in 'my character.' Thankfully he has such a forgiving heart and we're back to being great friends. He's always been there for me."
Their closest comrades aren't the only ones the happily married couple have made peace with, post-Hills.
David Becker / Getty
Reconnecting with Family"One of my many priorities after The Hills was to reconnect with my family," Heidi – whose mom told PEOPLE in 2010 that she could no longer pay her bills – said. "I realized I needed my family and life is way too short. I'm rebuilding my relationships with each of my family members. It's been about two years. My mom sent me a birthday card and I just started breaking down. So I picked up the phone and called her and she was like, 'Heidi! Oh, my god, Heidi!' It was one of the best moments. I was so happy to have her back."
Spencer has also made amends with his entire immediate family, including estranged sister Stephanie Pratt, who also appeared on their hit show. They see each other "all the time," he said, while she told PEOPLE on the same date at L.A.'s KIIS FM Jingle Ball concert: "He's become humble. The experience of the last two years – of losing his fame and spending all his money – has made him grow up. I have my big brother again."
Looking back, Spencer, a recent USC graduate who now lives with Heidi in Santa Barbara, Calif., says he never actually "felt a bad way" about Conrad.
TV Drama"I was just paid millions of dollars to pretend I didn't like somebody," he admitted. "And I'm a really good actor if you pay me millions. Somebody's got to be the bad guy and she's the good girl. If it weren't for Lauren moving from Laguna Beach, who knows if Speidi would be a thing? She didn't like that I was trying to make her show a hit show. I was trying to set up photos and be everyone's producer and manager. I knew what we needed to take The Hills from a good show to a controversial, dramatic, Gossip Girl-type show."
Despite no real animosity toward the Orange County-bred beauty, Spencer is bothered about how Conrad didn't take his relationship with Heidi seriously.
"Clearly she was wrong about that," he said. "She thought that someone so consumed with making hit TV wasn't in the relationship for the right reasons. I wanted everyone to have more success and I saw the potential it did have if it just got a little bit more dramatic."
No RegretsDespite a slew of surgeries (on Heidi's end) and a handful of altered relationships, the Pratts don't seem to regret their reality road overall, having met each other along the way. That said, they are currently looking ahead to a life of somewhat normalcy.
"I've been so serious about studying and school," Spencer said. "Being around this many super motivated USC students got me to see that none of these people really care about fame and it does not determine success in life. I'm competitive in nature and I needed to be competitive in success, and that doesn't necessarily mean being the top story on a website."
The gist of their life post-TV has been captured on After Shock: Heidi & Spencer, their new E! special airing Monday at 10 p.m.
With additional reporting by MIKE FLEEMAN