Coming up on a year later, and I think an update is in order for anyone curious or on the fence about this hobby.
No regrets yet. In fact, utterly relieved is still how I feel about going through with this. The idea to sell all my Lego came at a time when I was going through many changes, and it was definitely a necessary step in my personal development. I had a picture in my head of a new me that has slowly been materializing, and there was no room in that picture for plastic bricks.
In retrospect, the amount of money I spent on the stuff was ludicrous. I was on a one-way track to having an entire room walled with Lego, which at one point was a dream that I was working toward, but I eventually realized that it was not how I wanted to spend my life. I'd rather spend my time with friends or experiencing new things than building models in my basement until 4:00am. Even when I managed to find a nice balance with the hobby and not let it consume me, the rewards of collecting and building simply weren't there like they were when I was younger. Even my close friends, who thought my Lego hobby was awesome, agree that it was holding me back and tell me I've changed for the better.
With the money saved, I've spent over a year devoting myself to improving my image by building a professional wardrobe, working out for the first time in my life, and developing my social skills. I look and feel better than ever, and spend my time surrounded with the people I love.
Do I still think Lego is cool? Absolutely. I still check blogs and check out future sets, but have no desire to own any of it. A year ago, if I knew Lego LOTR was coming out, I would have freaked out and dropped a grand on it with no hesitation. Today, I admire the sets online, and leave it at that. I might still regret selling it in five or ten years when my life is more established, but I see myself taking up other hobbies then, like musical instruments or physical activities.
I hope someone gets some perspective from my experience. I still consider myself an AFOL.