I read GEB a few years ago, and it struck me as a book full of ideas that would have transformed me had I been encountering them for the first time. I think the book may have been so influential that its big ideas had largely filtered out into places where I'd encountered them. If I'd read it at 19, say, I think it would have rocked my world.
Note that I'm mostly talking about the book's first half (about incompleteness and canons and whatnot). The second half (ants, etc) struck me as much more dated.
I lost interest when certain other ideas made me think his basic project of accounting for consciousness mathematically was deeply flawed (and it wasn't Penrose's argument about formal systems!). I did find it entertaining though, so maybe I'll revisit before too long.
I'm curious what shift it caused for you, if you don't mind saying.
At least for me, it wasn't so much about computers or computer science, as it was the first time I really deeply considered what consciousness is. It's actually the book, along with The Selfish Gene that made me dismiss the necessity of any kind of 'soul', fresh out of Catholic School.
The more time I've spent reading about and considering the nature of subjectivity, the more I believe arguments from evolution or computer simulation are irrelevant. They're talking about something different.
