I think there is some confusion about google. Some people still view it as a small start-up but actually it is a huge web advertisement corporation.

Due to its massive revenue Google used (or maybe still does) to recruit lots of smart brains and frequently back then there was no explicit description on what they are actually going to do. That is one source of frustration.

But google is kind of good compromise of let me say between start-ups and the finance industry. It still has very interesting things to do and the salary is quite good compared to medium-sized businesses. In banks you may have to work very long hours and while burning out you do not have much time for family and friends. At least as Richard says it is paid well because that is where the money is. And it gives you a push of adrenalin as can be seen in this funny blog here. But the regular banking job may not appeal to creative individuals who want to contribute to something that is going to stay for some longer time and have an impact. In banks you may often build models but get rid off them quickly again once they no longer make you enough money. In start-ups you have a bigger impact and responsibility to influence the way the company goes in the future. Initially enthusially employees have to put a lot of time into it to get it started. You may also get business angel. But to attract venture capital you often have to prove actual revenues though this depends on the industry sector. And if the start-up does not work out you may also have invested so much effort and energy in your "baby" but the product was only temporary as in the banking sector.

I guess in the end you have to decide what kind of lifestyle you prefer, whether you have an entrepreneurial spirit or just want to be a working member of one of the big corporations. Yeah you may also like academia as another option.