MS might go bankrupt but it won't be due to letting old OSes die. MS Office isn't going anywhere soon and the corporate world will move onto Win7. How does the average home user acquire Windows? They buy a PC. Attrition will take care of that.
In his own gentle manner Mixture is correct. Seriously, the purveyors of malware must be rubbing their hands together waiting for April because they know oodles of users will stick with XP. They'll have any number of zero day exploits waiting to be unleashed and every XP system will be vulnerable in perpetuity.
If you value the data on your computer and your bank balance then please stop using XP online after April. Would you leave your valuables in a car that was known to be easy to break into? No? Why would you do it with a computer? Sure, you might get away with with it or you might not,,,,,
Yes, I know it won't necessarily be easy to make the move but there are ways and means to ease the migration. Investigate using XP in a virtual machine for instance. Just don't take the bloody thing online.
You've got six months so get cracking!