It is great to have all your digital music, movies, email and other entertainment available at your finger tips. In the past I have used a Shuttle PC running Linux to provide this functionality. Coupled with a 19" LCD and a decent sound system the experience is fantastic. Unfortunately there are a few issues I always faced. The first was the notion that Linux is 'free software'. Application wise Linux stacks up well to other operating systems. Gnome is a great graphical environment and applications like MPlayer, Evolution and MythTV are really first class. Whilst the applications and the open-source concept is great there are some areas where things are a bit rough around the edges. Many of these inconsistencies are not significant but I do find them annoying especially in a system you are trying to keep clean and easy to use by all. For example the visual difference in the XScreensaver prompt plus the difference in appearance between GTK/Gnome and Qt/KDE applications to name just a couple.
Many of these small inconsistencies are resolved in commercial distributions but I find it difficult to justify spending money on Novell/Suse or Xandros when almost the same is available for no charge. There is just no way I want to use Windows for anything other than games due to the number of insecurities and major system failures. So apart from a host of really minor operating systems I am left with Apple's OS X. OS X and its associated iLife range of applications are easy to use and stable but it has always been difficult to justify financially in a home entertainment system. Thankfully with Apple's release of the Mac Mini there is now have a home entertainment platform that is reasonaibly priced, works with all my peripherals (such as my 19" LCD) and provides the ease of use, stability and consistency I have been searching for in Linux without too much success. To top everything off Sync'ing my other devices (laptop, Palm, iPod, phone) is a breeze.
What Apple really needs to produce now is a PVR system along the lines of MythTV that does for TV/Video what iTunes and the iPod did for audio.