You have every right to recline, absolutely.
However, the nice thing to do is to take a glance back - or even (egads!) talk to the person behind you to give them fair warning. I have had my laptop screen nearly crunched countless times over the years by the person in front who could have given some sort of warning. It's the geometry of open laptop screen and the back of the chair being so tight. When the seat in front is slammed back, it can get hairy.
An annoyance that I have noticed as of late is people kicking/pushing the seat in front of them if it's reclined and it's time to eat. Again, a person has a right to be reclined the entire time, and a reclined seat is not that much of a hindrance to eating. It has never entered my mind to expect the person in front of me to put his or her seat up, but some people have come to the conclusion that they cannot function hand to mouth if the seat in front of them is reclined.