I've never been able to understand why the Linux filesystems are case-sensitive. Assuming you don't want to create files whose names differ only in case, the only result of a case-sensitive filesystem is error messages saying essentially that you used the wrong case. And that's just irritating, with no plus side. A well-designed interface minimizes errors. Maybe it's not a coincidence that both OS X and Windows use case-insensitive filesystems.
Yes, I know that NTFS is case-sensitive, but since the only documented way to access it is through win32, it's practically case-insensitive, unless you use you use your computer as a Unix server using Services for Unix. By practically case-insensitive I mean that you can open a file by typing in the filename with the wrong case from, say, the console.
This madness extends to web servers like a virus. Web servers should not return 404s for URLs with the wrong case. That's sheer madness.