One Googler said that the company is a great place to see, listen to, and meet with people who he grew up reading about ("Never in my life have I met so many people with a Wikipedia page than in the last year!" he writes).
Another Googler also had only great things to say about his coworkers:
We are surrounded by smart, driven people who provide the best environment for learning I've ever experienced. I don't mean through tech talks and formal training programs, I mean through working with awesome colleagues -- even the non-famous ones.
I've worked at several other .coms and have never been more challenged and energized professionally from my colleagues than at Google. People are generally happy to work there, they come from diverse backgrounds, and almost always have an interesting story to share.
Besides being exposed to tech leaders, there are often talks with celebrities and other thought leaders.