A quick entry tonight, just because the subject came up recently in this hint regarding iSync. In particular, the hint (and comments) note that iSync will fail if the application is moved into a directory whose name contains spaces. I had added an editor's aside about moving apps in OS X, and my personal belief that it's a Bad Thing to do. As noted in the second comment, it's not necessarily an issue with using applications -- they'll (more than likely) run fine from most any location. Instead, it's an issue with Apple's updaters failing if the application they update isn't in the usual spot.
Although it's my philosophy not to move Apple's applications around in OS X, that doesn't mean I'm happy about it. I have multiple partitions on my drive (partition vs. don't partition; that's a subject for another day!), and have one set up particularly for all my applications and utilities (called Apps). I put everything on that partition -- it makes it easier, for instance, to erase and install OS X if I have the need. As of result, the only things you'll find in my boot drive's Applications and Utilities folders are Apple's programs, along with anything that just won't run if it's located elsewhere (Tony Hawk Pro Skater 4, for instance, fails if it's not in /Applications). Everything else lives on my Apps partition. As much as I'd love to move Apple's stuff out of there, after reading about the issues people have had with upgraded applications not working, I've decided to just let sleeping Mail applications lie.