Any time someone's advice to buy something directly affects their paycheck, then their advice should be considered suspect. They have a strong financial incentive to look out for their needs, not yours.

Example: that friendly real estate agent who asks you about how much you can spend on a home, then pushes the limits to get you to buy the most expensive home possible is thinking more of his commission, not your needs.

A stock broker is just another salesman. Unless he works for one of the firms that don't pay their brokers on commission (Schwabb comes to mind), any advice is to be considered suspect.