Linux has a lot of work to do before it will be acceptable for the mass market. It is simply not ready for prime time. In the right hands (i.e. experienced) Linux is fabulous. It is fast, configurable and will support most hardware out there. Personally, I love it.
BUT, it is maddeningly difficult to get new hardware to work. It is maddeningly difficult to get your video card set up when you first install (xorg.conf anyone?). It is completely bewildering to get a sound card working if the installer doesn't pick it up the first time. Or, for fun, try getting permissions right on a new external hard drive that you plug in. How about the fstab (and other) entries for ntfs-3g? Almost mind boggling.
All of this stuff is easily enough done once you are in the know, but the average home user will not have the patience or the knowledge to manually dicker with fstab, xorg.conf and dozens of other config files to get things working. Until some Linux distros start arriving fully able to configure themselves on the fly, it will be too difficult for the average user.
Despite the goofy names however, Ubuntu is closest to achieving this. I would rate SuSE a close second. Neither of the above is "there" however. I will install "gutsy" and see if it is any closer in this regard. Every release, I keep hoping...