Broken record: the people. They can and often do turn bad days into wonderful ones.
Again, the people. Work is work. But if you can come in and work with people that you love each and every day, it's a huge life win.
The people. I have never worked with such a collective whole that is so amazing. We have no dead weight. Everyone contributes, and contributes a ton. This results in a very energizing environment.
We do make an effort to have a good representation of the people you will be working with in the interviews. This is largely because culture is so important. Personally, this is very important to me as well.
I'm paid competitively for the work I do. AND I am encouraged to grow. This isn't an explicit benefit, but any employer that is willing to invest $$$ in having its employees grow and develop is one to stick with.
Leadership is a vital and vibrant part of the team and play an active role in the day-to-day. They manage to be bother personable and professional. They care, and yet they are very hands off, as they trust their team to do their jobs.