/viewport aka looking up without looking up

[brussel]

I've been seeing these resolution and /viewport posts for a few days now and just cannot figure out what I am missing.

I swap between 4:3 and Widescreen and the bottom and top of screen are missing a strip. I swap back and forth between my original resolution and the 4:3 one and it just doesn't seem like much is lost.

My desktop/monitor is 2560 x 1440. What resolution and/or viewport settings should I try to really highlight the advantages?