eddieh - 9:27 pm on Feb 4, 2012 (gmt 0)
When I first starting building sites using Frontpage back in 19 dot dot, I always used to left align the pages (left hand navigation with content on the right). However, since monitors at that time weren't that big, it didn't really matter where the page was aligned to.
I then progressed to building sites using xsitepro always setting page widths to a maximum of 750px centered. Again, this was to accomodate the standard PC screen size of 800px. I stuck with 750px centered up until very recently when I started using a 950px width.
The extra 200 px of space allows for a wider left sidebar/navigation area while also allowing me to embed adsense units within the content without them standing out like a sore thumb. I have also increased page font size which gives mobile users a chance to actually read the content. I had tended to stick with 10pt font size but by the time that shrinks down to an ipod or ipad screen size, the text was becoming difficult to read resulting in high bounce rates by mobile users.
As regards the original layout on the left question, there are still plenty of sites that use that type of layout (think SBI), so they must be OK.
In any case, considering how close we sit to these oversized monitor screens, is it any wonder we have to move our head rather than our eyeballs to read what is on screen. How many times have we told our children not to sit too close to the TV screen and yet we do it all the time when on the computer.