Ubuntu vs Windows 7
[edit] Infection Possibility
Windows is sold with almost every PC. This makes Windows the number one operating system operated by most consumers. The result is that more malware, viruses, and Trojans are developed for Windows. Linux users are usually much savvier when it comes to general computer use.
Linux has been working on servers for near decade and was target to most sophisticated malware and learned from this constant beating. It has real tried-and-true nature. The source of Linux is open and shared, making collective patching and inspection as easy as it gets and allowing 2 hours reaction speed between detection of malware and release of patch (see Debian). Windows users will have to rely on antivirus updates to keep their machine somehow protected, until Microsoft or responsible company release a patch (if ever). This is also one of the reasons desktop Linux-based OS, such as Ubuntu, usually does not need any firewalling.
Antivirus companies do not exist without hackers producing malware. There has been speculation that Windows security is intentionally low, and that antivirus companies promote this supposed lack of security to better suit their own agendas. Of course, Ubuntu (and all Linux-based operating systems) is not immune to computer viruses, as is evidenced by the implementation of such free Antivirus software programs as ClamAV. Ubuntu does offer the advantage of having far fewer viruses and malware that can run on it. This is mainly due to two reasons: 1) Ubuntu is a Linux distribution, which inherently has enhanced security measures, and 2) There are far fewer users operating Linux-based operating systems. Naturally, hackers will target the operating systems that have the largest user base. The main short-coming for most average Linux users is that they do not run any antivirus software at all - either paid or otherwise. This in itself could increase the chances of those said users to be able to harbor or become victims of malware - or both. Additionally, as the Linux user base increases, the community could potentially see an increase in malware available for Linux-based platforms.
Antivirus software relies mostly on heuristic methods to determine whether the software in question is dangerous. These methods are highly unreliable. They also use virtual machines and virtual execution and analysis before actual execution, this however, is no-saver as modern malware can obfuscate, mutate and update itself on its own.
Linux has very deep, yet simple and efficient file rights management out of the box and additional restriction mechanisms available. Windows started implementing same starting windows 2000, but even today its security model is weak.
Linux has "ability to be executed" as access parameter and utilizes NX (no execute) together with memory address randomization (where available) very efficiently, where Windows relies only on file MIME types to determine if file is executive(very often mistaking and executing "pictures"! See 2010-3970 as most recent entry).
Ubuntu software is updated centrally and automatically, making the application of security patches centralized. In the past, Windows users were required to search for, and install, the latest security patches themselves. There have, however, been improvements in this area as Windows Update was redesigned for Windows Vista and Windows 7. Many third-party software vendors have also increased their update features, but this still leaves a large margin for error, as Windows updates and third-party software updates cannot be managed from one centralized location. Due to the central and open nature of FOSS development, it is very unlikely any malware can make it into the repository. Be aware however, that closed source software, which is also available for Linux (such as Adobe Flash) has long history of un-patched vulnerabilities. Updating both OS's and using extensions, such as NoScript is useful for both.
Linux kernel binary interface is much more unstable than that of Windows. This leads to situation, where with change of kernel compiler, system C library and its version - all binaries must be recompiled or they will break. Windows however has been trying to maintain compatibility with older revisions and APIs for years. Because of this infecting windows by exploiting errors is MUCH easier as well as Windows has a LOT more old crap and bloat in form of outdated libraries. Still, the compatibility with legacy on Windows is not that great (but its non-existent on Linux, either application is maintained or it will eventually disappear because of breaking).
Windows software usually costs much more than of Linux equivalents. As such many people are downloading the software illegally and many crackers integrate malware deeply within their releases, making such windows-machine zombie (part of botnet) as soon such software is installed.
[edit] Software Choice
Because Windows has been primary desktop platform for years, Windows has the most software available. However, if only the newest or most up-to-date software is considered, the value will be lower, but still will beat Ubuntu, especially at Gaming.
The most drastic difference can be seen in Gaming, where Microsoft has been pushing and polishing its DirectX exactly for the purpose of games to relate on its Windows-only technology than on feature-comparable crossplatform OpenGL. This is however again changing, due to OpenGL availability for smartphones(android), consoles (ps3) and Macs. Apart from it, the project exists to make free implementation of Windows API available on Linux and Unix systems making running of Windows-only software at near native speed possible (See WINE). Ubuntu is OpenGL capable, has increasing number of games and is capable to run at least 2/3 of Windows-only titles via WINE, 1/2 of them perfectly. Sometimes even better than on Windows.
The current area where Linux lacks software choice is Flash editing. Adobe, the authors of Flash, refuse to provide any Flash productivity suite for Linux.
As application development platform however Linux software choice is larger than that of Windows.
Overall amount of software for Ubuntu should be more than enough for its use as Desktop OS. Most of software, unlike on Windows, is free and usually opensource.
[edit] Maintaince
Ubuntu does not need its drives defragmented(except using non-extX based FS), it does not need any special tuning, software installation is done very quickly and from one place, its kept on current status automatically, the system overall is very predictable.
Windows does require more maintaince time and much more setup time, however it may be operated without internet access, using only distribution media. Amount of software available for linux on such media is lower, except the user downloads needed packages online somewhere else and installs them offline.
