% of main OS:
Desktop OS market share
as of September, 2008
Windows - 88.26%
Mac OS X - 9.93%
Linux - 0.83%
Other - 0.98%
Wiki did a big comparasin of Windows and Linux. I will not be describing each subject in detail, but instead I will only highlight which one wins according to me.You can read more about it by clicking on the link at beginning of the paragraph.These are just my views, This is how I see the difference between Linux and Windows. Feel free to post your views.
Cost (O/S + basic software i.e office

Windows Linux

Linux is free, for a basic Windows setup expect to pay in excess of $300 (£150)
Market share
Estimated Desktop Usage Share

Windows Linux
Pre-installation

Windows Linux
I guess it's easier to use for any Tom, Dick, and Harry
User interface
Graphical user interface

Windows Linux
more choices of customization
Command-line interface

Windows Linux
Linux has severely extended file names and difficult commands
Installation
Ease of Install

Windows Linux
both are easy to install
Install time

Windows Linux
standard installation about same
Drivers

Windows Linux
Over 99% of drivers are for Windows, Linux must find scraps
Installation via Live Environments

Windows Linux
LiveCD Rocks.
Pre-installed software

Windows Linux
More choices on start-up
Not pre-installed software

Windows Linux
Windows has wider selection
Partitioning

Windows Linux
File systems

Windows Linux
more native support than MS
Boot Loader

Windows Linux
Linux has one already build-in. Sucks that you have to install Windows first.
Accessibility and usability
User Focus

Windows Linux
Need more info on this
Consistency between versions

Windows Linux
More uniformity would really help Linux.
Consistency between applications

Windows Linux
Same as above.
Customization

Windows Linux
FREEDOM !!
Accessibility

Windows Linux
Not everyone speks Inglish
Stability
General stability

Windows Linux
I am still haunted by BSOD
Device Driver stability

Windows Linux
Both have stable drivers on my system
Downtime

Windows Linux
don't like rebooting, Linux hands down
Recovery

Windows Linux
Windows has certain issues that need to be worked out
Unrecoverable errors

Windows Linux
I think BSOD was my desktop wallpaper on Win95
Hardware Abstraction Layer

Windows Linux
Need help with this subject
Performance
Process Scheduling

Windows Linux
Windows is finally learning it's mistakes.
Memory Management/ Disk Paging

Windows Linux
MS developers should take notes from Linux.
Corrections Needed

Windows Linux
Need help with this subject
Support
Community support

Windows Linux
Both have their ups and downs, but for me they work same.
Phone support

Windows Linux
Never used either one.
Documentation

Windows Linux
Sorry, Windows documentation is much easier to understand.
Training

Windows Linux
Both have strong and weak points.
Third Party Documentation

Windows Linux
Almost everything is build for Windows
Programs
Binary Emulation, Alternative API

Windows Linux
MS is too proud to run other OS programs.
Hardware emulation and Virtualization

Windows Linux
both have same possibilities.
Operating systems run as application

Windows Linux
Need help with this subject
Package management system

Windows Linux
Linux has too many different installers.
Adding New Programs

Windows Linux
Windows has better selection, but I love package manager. Installing software that is not in Package Manager can make me very cranky..
Updates

Windows Linux
Windows only checks for it's own updates. Linux checks all software.
Cross-platform (software)

Windows Linux
I guess majority rules.
Cross-platform (development)

Windows Linux
Need help on this subject
Cross-platform (hardware)

Windows Linux
Need help on this subject
Backwards Compatibility between releases

Windows Linux
Every tried running XP program on Vista ?
IDEs & Compilers

Windows Linux
Generally, both can have same result.
Gaming

Windows Linux
Most (if not all) are written for Windows, not Linux
Security
Malware

Windows Linux
"A nail that sticks out, gets hammered"
Open vs. Closed

Windows Linux
MS afraid of competition ?
Response speed

Windows Linux
Speed makes the difference
User Accounts

Windows Linux
MS finally noticed something that Linux has been doing for a while
Filesystem Permissions

Windows Linux
MS let's you play "god" on your OS, but clueless Joe Shmoe can quickly screw up the system
Localization

Windows Linux
Speak Tày better than English? Use Linux //Me love you long time!
So, out of 50 differences,
Windows gets 12

Linux gets 22

,
There are 9

meaning both are about the same.
And there are 7

, which I had some trouble comparing.
Please keep in mind, that these are just my views.
So why is Windows more popular than Linux?
Ease to use
* 99.9% of Windows applications have GUI, while Linux depends heavily on text commands. Example: In Windows, I can set up VNC server with just few clicks, but in Linux, I still can't properly set it up the way I want. It's easier to just click, than to type in commands.
* If you have trouble with some software in Windows, a simple visit to developers website can answer your questions. Most developers do not support anything else than Windows.For Linux support, you have to depend on others to help you out.
Availability
* 99.9% of hardware and device drivers is supported by Windows. I still can't use my PVR-660, my printer or my HTC phone on Linux. I don't even have proper drivers for my display adapter.
Popularity:
* MS has paid employees, while Linux has free developers. Most people figure, that if it's free, it's probably half-a**'d and not entirely complete. Would you trust free mechanic to work on your car?
* Ever tried to suggest Linux to every-day soccer mom, that uses her computer to read celebrity news? It's like inviting a devoted catholic to strip club.
There are few more points, which i will add later on.
So what are your views ?