Question of the Day: Age

When it comes to dating, how much of an age difference is too much?

Answers I've received so far:
~ Um, maybe a chick over 40 would be too old. (Note: This guy is in his early 20s.)
~ 20 years
~ So long as he has a job, a home and his teeth, and he knows how to treat me, I don't much care if he's older or younger.
~ 25 years

My answer:
It all depends on the people involved. That said, I think one generation is a safe age gap, but not much more. Why I'm using generations instead of years: I think a relationship's dynamic depends upon things like (1) having similar upbringings (e.g., someone who graduated high school in 1960 might not have the same values as someone who did in 1969. Think Bandstand vs. Woodstock.), and (2) being able to "get" each other's pop culture references. If one of the two people is under the age of 25, the gap really shouldn't be more than, say, 5 years. The reason for this goes beyond the dynamic; it's about maturity and mindset. Of course, all of this is a generalization, as some of the most enviable couples I know have quite a big age gap. Perhaps their success is not in spite of the age difference, but because of it?

(Post your answer as a comment.)