Sunset Jamaica Grande is very near the port, you can do an all inclusive, and they have a water park:
There are a number of private tour options:
Last time I just got off the ship and walked around - No Problem, Mon!
My pictures: http://www.zydecocruiser.com/free_08/thu.htm
I love Jamaica - been there on both land based and cruise vacations. Yes, some of the vendors can be a little pushy but understand no. How well they understand it depends on how firm your no is.
I think overall, it gets a bum rap.
Oh yeah, here were some taxi prices as of last November: