I'm so famous! I love it.

Your answer really depends on what kind of deal you can find on a pre-build wheel vs. what your LBS charges to build/rebuild one. If you've already got a good hub, I would suggest having it laced to a new rim...especially if you're planning on going deeper than 30mm. I can't speak for all shops but I know the one I work at would knock some money off for the exchange of spokes, assuming yours are in good shape and can be reused.