At my day job I am maintaining Linux (Red Hat, Fedora, SUSE, Debian) and UNIX (Solaris, HP) servers and I really enjoy working with those operating systems, but those are not for desktops because of lack of tools, they are for servers and they are perfect for them. Specially if you consider a price factor. It makes a significant difference if you have to choose between 100 web servers with free Linux or the same number of Windows machines. Not to mention that almost for sure Linux machines can give you better performances and more stability. I think I have read somewhere that Debian + Apache is the most stable and most used combination for web servers.
Unfortunately, even with my solid experience with Linux, my every attempt switching completely to Linux on my desktop machine ended with coming back to Windows. Simply I could not find a Linux replacement for every software I need
