If you are just trying to develop the next Unix clone of telenet or ftp, this argument might make some sense. If you are working in any sort of commercial environment, the cost of the PC is just a rounding error.
This entire subthread about the putative costs of a generic x86 box vs. something from Apple is absurd - nobody cares about these sorts of costs except poor hobbyist programmers -- and none of the companies, Apple included, gives a tinker's damn about this demographic.
For mid to upper range laptops*, Apple is very competitive with everybody else. If you like the tight hardware / software integration that MacBooks offer, then great. If you don't care or really want to run Windows, go get something else. I do wish that Apple had a few more choices - I'd love for them to resurrect the 17" MBP, but I'd also like Dell to have English speaking customer facing employees, for HP to make keyboards worth a damn and for Toshiba to simply go away.
But life is hard....
* The Mac Pro, especially the Darth Vader's ashtray version, is really a niche product