I've got a 23" monitor, with a resolution of 1920x1080. It's pretty awesome. (Dell Ultrasharp U2312HM)
My previous one was a 17" monitor, 1280x1024. So that was a pretty good upgrade.
Well, besides the actual improvements to the screen and the massive improvement that is upgrading to widescreen, you actually washed out

1280
2 + 1024
2 = 2686976 | sqrt(2686976) = 1640 | 1640 / 17 = 96.5 PPI
1920
2 + 1080
2 = 4852800 | sqrt(4852800) = 2203 | 2203 / 23 = 95.8 PPI
As much as it pains me to admit it, Apple is the first company to push for an actual increase in monitor PPI for consumers in a long time...