My knowledge of Audio gear is pretty solid. No surprise there since I've been a very active audio buff for over 30 years now. I don't think I've had any earth shattering revelations since joining Head-Fi, but I have learned a lot about DIY audio since joining here. Not actually how to build things, but a better knowledge of what's available out there, and how it scales compared to the boutique stuff.
I've also made some very good friends. Some that I've met face to face with on numerous occasions, and some that I've only been able to converse with here or on the phone. Those friendships are invaluable to me, and I have Head-Fi to thank for them. Some of those friends have built gear for me, and that makes it not just gear, but handiwork with a very personal touch.
I've also been lucky enough to merge my two favorite hobbies, and have been thrilled to see some of the fruits of my labor sent to all seven corners of the globe.
So though I tend to get sarcastic and a bit whiny now and then, that doesn't mean that I'm not fully aware of what this site has given to me. Aware and grateful!