Time was all I cared about was getting an elite level so I could board early. I would qualify on 4 airlines each year. If I got one free ticket a year I would just give it to my Mom. I joined all of the hotel plans so I could get upgrades and a free paper.
Last year I got a bigscreen TV and a 130mm computerised telescope from AMEX using points and a power washier form ICHotels.
Plus I still have a million airline miles left after taking a few trips!
But you have to have clear goals in mind. And many plans do nothing for you if you do not use them. The AMEX plan costs 50 dollars a year to play. If you didn't spend at least $5000 on AMEX it was not worth it.