Hmmm. It sounds like you're defining "nice guys" as "guys who make an effort to 'be nice' for the sake of being able to call themselves nice guys," whereas I meant the term to include guys who are just naturally nice. Going by your definition, I agree with you completely; going by my definition, I certainly prefer people to be genuine, but I also tend to like them better if one of the things they genuinely are is nice (for some vaguely defined value of the term).