Just to make a quick comment from one of the stories that involved "switching" applications:
"For example, what Apple could do is put together a Web application for a new OS X user to enter the Windows software that they would like to switch to Mac software .... But the process of trying to contact all the companies individually to see if they'll let me switch the Mac versions is time-consuming and unreliable enough that I doubt if many would do it. "
In a fortunate circumstance, many of the day to day development tools I use on a daily basis are Java-based. Specifically, Turbo XML, IntelliJ IDEA, Perforce and BEA Weblogic, do not require different licenses or versions, just enter your license key. (Be sure to follow the stipulations...)
As far as me the developer, moving from developing on the Windows/Linux combination, Mac OS X has saved me a *lot* of time and headache.