I respectfully disagree with the so-called popular vote. As a developer I can honestly say that I would not go back to XP for several reasons, let me count the ways.

• Windows XP has over 300 patches since it's inception in 2002, most of them security related.
• Windows XP allows malicious applications to affect low level system processes (i.e. Keyloggers and such).
• Requiring administrative rights to launch a desktop application is a security flaw, they fixed this in Vista.  This is one reason why some older applications no longer work as they should.
• The memory management is not what it should be, you start seeing a degrading of memory usage after 2Gb.  With 4Gb of memory in Vista you can open 20 applications and they play nice together, this was never the case with XP.  Anyone who says this is an issue does not understand how the OS allocates memory, trust me; you will love the way your applications work on a properly configured system.
• Virtualization does not work in Windows XP, if anyone tells you it does they are wrong. 
• You have to reinstall Windows XP every 2 years to remove unnecessary garbage, I haven't seen this problem in Vista.
• Once Nvidia/ATI corrected their graphic drivers Vista didn't crash anymore, this was never a Microsoft issue.
• Without installing a single anti-virus program Vista is 60% more secure than XP according to the latest studies.

The fact is you cannot expect poorly written applications to work forever and you cannot fault MS for building an OS that enforces good coding practices. Apple works because they don't have to support third party hardware, it is very proprietary and very expensive to repair should you have issues. Linux is not simple and the interface still leaves a bit to be desired so quit recommending it to novices as it will not make your computing life easier and yes, I did install the latest version of a popular Linux distro within the past few weeks so my opinion is fair.

Microsoft did not write a bad OS, they simply exposed the poorly written applications to the average user.

Move forward, throw out those poorly written apps and embrace a better world.