I'm new to Eagle, but am a long time user of various CAD software programs, and am finding the layout editor in Eagle very basic. I'm hoping that version 6 finds some great improvements to the layout editor. Some things that I would be looking for:
1. The ability to measure distance of pad and wires from one another.
2. The ability to move the origin around temporarily (not the Mark command).
3. Alignment options to be able to align sides of object together.
4. Relative offsets. To be able to place objects relative to some other object.
5. To deal with pads with absolute coordinates, not one based on the center of the object.
Check out TurboCAD for Mac and follow their lead...