if you read the manual then you can see that a lot of the items they do in these services is just checking things. If you learn how to check them out then you can just spend 3-4 hours and check them yourself, change the oil, and only pay the dealer for the individual services that you are not comfortable doing. (Such as valve adjustments for me at 26,600 miles would be something i would pay for, other than that the 16k service has a repack of the swingarm bearing and change coolant... the spark plugs are supposed to be replaced at 8000 mile increments, but other than that is is a whole lot of looking and checking on things that they are charging you for.
The owners manual tells you what they "should" be doing during these services and i doubt that i would pay for the whole service.