The Intel GMA will performance worse at handling "DualView" mode over the ATI/nVidia cards. Atleast get the x1300 ATI card if you plan to run TV-Out or an additional external monitor.
If you want to do high resolution external monitors and the laptop screen at the same time, get the highest video card available. It has to do with the GPU Core's ability to handle that much resolution - which is similar in the way it handles high loads from games on a single display.
If you get the dedicated graphics on the E1505 you won't have the option to upgrade to dedicated graphics later, I'm not sure if the same holds true for the E1705 with Intel GMA950 - don't think anyone here has received one yet and cracked it open to look yet.