On OS X:
1) arrow keys move an object around by one pixel.
2) cntrl + arrow keys move an object in 10 pixel increments.
3) optn + arrow keys move an object in 20 pixel increments.
4) add the shift key to any of the above combinations to resize an object instead of moving it.(!)
5) And the best yet: all of the above work on multiple objects selected.
- david