[alt text: a photo of two kids sliding down two separate playground slides (chutes) that are side-by-side but end in the same place. The left slide is captioned: "Being a slacker at work". The right side is captioned: "Being the go-to-guy at work". The bottom part where the slides meet is labeled: "No raises".]
The secret I've found to a wonderful work life balance is to become indispensable in knowledge, but to not do much or any labor; just be a walking encyclopedia for your job role that enables others to do their's.
For managers who do not yet understand your new work dynamic, make sure to say 'yes' , very enthusiastically, to whatever they ask, but then just don't actually do it. They'll learn to stop asking, but they can't afford to lose you either.
Rejoice, you are now an "SME".