But in 2015, Windows 7 will go onto extended support, which just covers the basics. You'll still receive free security updates, but non-security-related hotfixes will only be available on a paid subscription--and you'll have to start the subscription before April 15, 2015 (if you live in the USA, that's a date with unpleasant associations in any year). There will be no free support, Microsoft won't honor warranty claims, and the company will not add new features.

By the way, XP's mainstream support ended on April 14, 2009; Vista's ended on April 12 of this year. So if you're satisfied with the support you're getting on this operating systems, you probably won't have much to worry about with Windows 7 for another seven years.

For what it's worth, XP's extended support ends on April 8, 2014. Vista's will end on on April 11, 2017.