Here are some pics. I don't run 1:1 because of how it looks on my cable input. See, I have an HDMI to DVI cable. The 2407 can not handle a 1080i connection because it just can't. There is no interlacing on the DVI/VGA ports. The cable box can only do 1080i. So anyways, here is how it looks at 720p.
720P
Fill
Aspect
1:1
1080P
Fill/Aspect
1:1
Pics look washed out because I had to boost the contrast so you all can see the monitor frame. For 1080p, fill/aspect are identical. For 1:1, it increases the black bars by another half inch top and bottom.
As you can see by the 720p 1:1 - I don't run it for that reason. Since I run an HDMI switcher, the monitor sees DVI as 1 source so whatever I set it to do, it does no matter what. It can not differentiate between hdmi1 or hdmi2. It's all the same. That's why I don't run 1:1. Either way it looks good to me
Hope these help someone.