Hi,
I've committed a couple of patches to the grid behaviour, after discussion with Buila on jabber. If anyone has problems, please say so and I'll fix or back out the patch.
1. Removed feature where alt-drag provides a "slow drag" when moving objects.
2. When moving objects, alt-drag now moves them without snapping, even if the grid is enabled.
3. When moving objects with the grid enabled, the current behaviour is to snap the objects "snap points" to the grid. This patch adds an alternative behaviour on Shift-drag: moved objects are snapped such that they keep the offset from the grid that they had before the move.
4. When you paste an object it is pasted at the same offset from the grid as the original.
5. An option in Inkscape preferences to make (3) the default and the current behaviour happen on Shift-drag.
My rationale for (3), in case anyone's interested:
It's basically for doing simple line drawings. Draw a simple shape made out of straight lines, some of whose points are snapped to the grid. Now if you move this object around, the bounding box of this object will be snapped, rather than the points themselves. This means that the line position plus its width will be snapped. If you then try to draw another line which joins to the object you've just moved, the new line's points will be snapped. Hence the old object and new line will not meet up, being offset by half the line width.
It's possible that this would be better implemented by improving Inkscape's ideas of what "snap points" are, but the end result would be similar.
Thanks
Carl