We've enjoyed our meals at Milliken's Reef, and the view is the best of all of them...you get a great cruise ship dock area view before and after, and a nice long look as the ships turn into the channel. Plenty of tables not near the windows, though, so you never know.
For not eating, just watching, nothing comes close to Jetty Park. What a blast strolling around, putting out chairs to watch the ships!