I moved on from XP 10 years ago, and believe that every OS released since then (including Vista) is far superior. While I loved XP when it was released, I really don't like it compared to more recent operating systems. So, aside from any security concerns, I simply don't like XP anymore, and I even would much rather use Vista (which is a highly underrated OS in my opinion). However, on the other hand, I really don't believe that using XP is as much of a risk as people believe.
To satisfy my own curiosity, I will test XP. I am going to install XP with SP3 on one of my spare laptops. I am going to install all Windows Updates, but will not use the POSReady hack to continute getting updates, as I presume this is something the average XP user would not do.
I will do absolutely nothing to secure the computer, other than leaving XP's built in firewall and Windows Defender enabled. Of course in XP (just like in Vista and Windows 7) Windows Defender is just a very basic anti-malware program, rather than being a full antivirus. I will install some demand scanners.
I will probably use Yandex for the browser, and I will do a lot of web browsing, including visitng potentially risky sites. The only precaution I will take, is to never run unknown files. I will run scans from time to time, to see if my computer gets infected. While I have no doubt that it's safer to use a more recent version of Windows. Personally, I believe it won't get infected, but maybe I'll be proven wrong.
As a final note, I must point out that there will nothing of importance stored on this laptop, and I will never enter any personal information into any of the sites I visit.