I'm probably an asshole to say this, but I'm reasonably sure I could've gotten a job with Google in 2001-2; and at that point I didn't want to work in that kind of office. I went back to LA and drove a taxi for a year and a half, and wrote a novel, to clear my head.
The thing that makes me flinch about it is the competitive nature of the job, even if your job shouldn't have to be competitive. The open offices, the personal time, all of these things make you run faster rather than being allowed to slow down and think. And if you get to thinking about who you're running for...who knows? As insulated as you are from the clients -- which is great -- you also almost never get to see the direct result of your own work. So what emerges is this endless Senior Year of High School, where everyone's waiting to be recommended or get their acceptance letters, while partially slacking off while looking like they're on their best behavior. I'm not sure that's a way I'd be willing to spend my life.
I make about 1/5th what you do, probably, for about the same level of work and commitment to my own startup. But I don't envy your job.