At the end of the day though - it really does depend on what correct
means to you.
1. Do you want to make sure that your pages are closer to strict HTML -
which means that in complex pages, the browser will stand a better
chance of displaying what you want
or
2. Do you simply want to ensure that the browser you use displays what
you expect - if so - strict HTML isn't necessary; so long as it works
for you.