Well, I beg to differ regarding the AGP and Slot1 combo. Win2k will allocate resources and share the irq regardless of where you put your second card. I have three different systems running an AGP with the second video card in slot1 without any problems. As long as the system is ACPI compatable, I wouldn't give it a second thought.
On my latest system, the AGP was a Matrox G400 SH and I used a 8Meg Matrox G200 in slot 1 and loaded win2k while both were installed. I then proceded to update the drivers, and that was that.
As for the 19" and 17", that's what these systems are running. I use the 17 as the second display for an additional browser, management tools, Explorer, etc...and I use the 19" for the majority of information. I also found the best res for eyestrain to be 1152x864 on the 19 and 1024x768 on the 17. The fonts and windows are almost the same size so the screen dosen't jump around when you drag a window between both monitors.
Just a humble opinion....