I have a 24 inch dell monitor at my work. It works great and has a higher pixel density, but the difference in pixel density between 17 and 19 inch is none, so go with the more clear display, the 17" Ultrasharp
First, whats pixel density if you dont mind explaining. And, I do like having a bigger screen, so I can do more at once, because, I can put more on the desktop. So, havint hte 19'' does have its benefits.