Very few sites aim for 960 as their minimum[1]. I tried side-by-side viewing on a 1920x1080 monitor and it really didn't work out in most places. Even parts of Wikipedia (such as tables) will create horizontal scroll bars on certain articles.

I did notice that a lot of websites aim for 1024 instead of 960 because I saw many pages that almost fit. Please, if you can aim for 1024, aim for 960 instead.

[1] As the parent post said, it probably isn't quite 960 when you take window borders into account.