People have varying (and sometimes very strong) opinions on seat reclining. There are already a lot of threads on seat reclining...a sampling of recent threads from various forums:

Live, Interesting Seat Recline dispute, what would you do?

Recline Seat for Nine Hours?

Economy comfort and seat-recline bullies

OT: Seat recline etiquette... the hard way.

Are you willing to pay the person in front not to recline?

Now for a real pet peeve.... Reclining seats....

Reclining Seats

Seat reclining during take-off: rules and etiquette question