As a guy in my mid-20s, I find two things interesting about this thread:
1) Most of the advice is about managing finances. Is this really the most profound thing that people learn about life after college? If so, I'm much less excited about the next 50 years.
2) A lot of the people giving advice contradict each other about things they "know", i.e. save for retirement vs sell your 401k, get married vs. don't get married, try in school vs don't try. It makes me think that a lot of the truisms that we hold dear are the product of our interpretation of successes/failures that are more or less arbitrary in nature.