9) Linux supports less hardware than Windows.
Windows supports more "specialty" devices and chipsets than the Linux desktop, for sure. But in terms of sheer numbers of supported devices out of the box, Linux destroys Windows.
Remember, you don't generally see a "Linux driver" on the CD that comes with a new computer hardware purchase. Motherboards, video cards and sound cards will almost always work fine right out of the box. Where things for Linux can get especially sticky is with select wireless chipsets built into wireless USB dongles.
Manufacturers change these chipsets often, but will keep Microsoft happy by providing a drive CD for users of the Windows operating system. Even with the great skills possessed by the various Linux developers, operating a crystal ball to be able to keep track of these things just isn't possible.
10) You can't easily run multiple monitors with Linux.
At one time it was true that you couldn't easily run two LCD monitors at the same time without editing a configuration file. These days, however, it couldn't be easier.
By simply using an ATI or NVIDIA video card, you'll find that running an extended desktop across multiple displays is very simple to do. Multiple monitors on desktop Linux now offers the same ease or complexity as setting up display settings within Windows.
11) Linux has terrible printer/scanner support.
Going back to an earlier statement I made about how many non-geeks actually install this stuff is relevant here. Even "perceived problematic" brands like Epson or Lexmark are now making Linux support more available through their websites.
The key to success is to either have the less advanced user run with printer/scanner models known to work out of the box or have the in-house Linux person install the relatively simple-to-install Debian or RPM package with the driver update. Even excluding support from the manufacturers, the SANE and CUPS projects ensure that we have plenty of great support for most of our printing and scanning needs.
12) Linux doesn't play well with webcams.
Just like with printers and scanners, manufacturers are beginning to wake up to the fact that Linux users have money to spend. So it behooves these manufacturers to provide basic Linux support without any unneeded hassles.
I own multiple Logitech webcams and they all worked out of the box. Even when venturing away from the Logitech brand, you'll generally find that the Linux platform has covered their bases with the commonly used webcam chipsets for USB and integrated webcams.
My brand new ASUS Eee netbook, for example, has a working integrated webcam that works great without any extra effort from me whatsoever. No driver CD, no compatibility list, the webcam just works perfectly.
13) MP3 player support is non-existent with Linux.
It's funny, in 2011 when you mention a portable MP3 player, most people think of the iPod. To make matters worse, Apple-based devices are one of the biggest headaches for developers to backwards engineer as Apple worked extra hard to make sure you will not be using "iAnything" on the Linux desktop.
Despite many projects making Apple devices compatible, it's a losing battle. The truth of the matter is that most portable MP3 players work great out of the box on the Linux desktop. There are many other brands out there that are open about their embrace of the casual Linux enthusiast. For example, check out JetAudio's iAudio devices.
14) Most USB devices don't work with Linux.
External hard drives, DVD-burners, a Flip video cam each of these works fine out of the box. I have never purchased a non-Apple based USB-based device that was incompatible with my Linux desktop. From digital audio recorders to my Flip Video recorder, everything just works and I have no complaints. Most people who claim otherwise are simply wrong or are speaking based on second hand information.
15) There aren't any good games for Linux.
The Windows desktop and (to an extent) even the OS X desktop are demonstrating their "power of market share" when it comes to the top notch computer games available. Despite this mark against the Linux desktop, there are still some pretty cool games available.
Most of the available games are mashups or open source-based. For those who might be interested in trying one, just do a search engine query for "Linux video games." You may be surprised at just how many options there really are.