D.P.
In a job situation, the best thing to say for weakness is "Oh, my strict attention to detail and perfectionism"! ;)
On a personal level, I would say that my strengths are the ability to "read" people from the get go, my loyalty to my friends, my sense of family, and the ability to think clearly and logically.
On the weakness side: procrastination (better now that in the past), aversion to filling out ANY type of paperwork, I'm a soft touch for an underdog story OR a sob story, and a very real and deep appreciation for anything that combines chocolate and peanut butter.
p.s. Here's a better interview question: What are the last 3 things you've read? (Speaks volumes about a person - no pun intended!)