Totally agree. However, to 'filter it all out' is a onetime occurance now that I put Ubuntu + XFCE on my parents PC.
The hassle of Updating the OS, Updating the Antivirus etc etc are now all minimized to a bare minimum. Every week or so I run:
aptitude -y -R full-upgrade
And I'm done. Windows Updates was a nightmare. Windows XP doesn't receive any new browser and multimedia support from Microsoft. Using third party tools didn't resolve the problem.
I have to confess, the start was rather troublesome especially since my parents have to get used to Linux after using Windows for years. But in the long run, I believe the benefits outweight the drawbacks. The machine is capable of handling the tasks it users demand. Linux provides this facility at a (somewhat small) startup 'price'. But once it runs... . And besides, I wait on how Windows 8 turns out. If it becomes another fiasco like Vista (which came on my laptop), you are left in the dark way earlier!
I agree that buying a 'new one' might be better. But I'm still waiting for stuff like Secure Boot and GPU drivers to become better.
If you like to microoptimize, you should use LXDE. xfce isn't anywhere near as lightweight as it claims to be, and with LXDE you only get what you really need.