Windows 10

[viper37]

Windows 10 is going to be 249$ come July.

And there's a strong possibility it will install by itself, without warning, before that, if you have Win7/8.1.
Might be better to do a controlled installation when you have some free time, double check that everything is working as expected.  It will avoid calling on a friend, in total panick, late at night, because Windows 10 has fucked up your printer and slowed down your very old computer

[MadBurgerMaker]

They changed it to a "Recommended" update at some point, I think.  Sneaky.

[Phillip V]

I will wait until June when my bosses are on vacation.