As far as investment banking goes, I think the culture is exceptionally good - I have heard horror stories across the street. I think culture is very team dependent - the reality is, 95% of day to day interaction is intrateam, and the culture of individual teams varies significantly across the floor. For my team, everyone is cordial, willing to help one another, and there is no culture of back-stabbing and throwing people under the bus to get ahead. This is particularly pronounced at the junior level.