Apple's laptops are simply great machines. With the current generation MBA on the plate... this statement goes doubly so. Refurbs go for under a grand, and they're very, very fast for normal day-to-day stuff... not to mention the form factor and silly good build quality.
That said, there's one segment where I think a hackintosh laptop makes sense: Netbooks.
I have a hack Eee 1005HA, running 10.6.X, for my developing world travel/photo backup needs. Reason: It's plastic, silly cheap, and kinda ugly. If it gets stolen/broken, I'm not out a grand. It doesn't attract the attention a MBA would. It's taken quite a beating, and keeps running. But it's slow... perfect as a backup device with a 500GB HDD for being on the road for a few weeks.
I'm definitely eyeing a new MBA sometime in the next refresh cycle for all other laptop related duties!