Many people seem to think of the company as having a "startup culture", but in my experience, that is far gone. With cost savings in mind, management has taken away a lot of things that keeps employees happy. The benefits package is average, the "healthy food" breakfast has been trimmed down significantly, and there are few perks such as rewarding good innovative ideas. Compensation is based on average market forces in the area, etc.
The office dynamic is fairly mixed. As a cost savings measure, many software engineering positions are off-shore creating a VERY poor work/life balance. With the time zone difference, you would be expected to work at 10pm-11pm or come in early between 7am-8am just to communicate with the rest of your team. This creates a very tiring cycle of work which makes it very hard to be productive during the day. In addition, the significant amount of work off-shore is starting to have an impact on the quality of the software being wrote which as Software engineers, you'll find to be very infuriating to work with.
Another significant office culture dynamic is the increasing amount of contract work. Although you may find yourself with a better work/life balance, our fellow contract co-workers are facing even more harder work conditions simply because HR doesn't handle them. This causes an increasingly stressful work environment where people are becoming less relaxed and less "startup culture" and becoming more of a company where people are expected to be worker bees.