I use guide lines a lot. For everything.
I would like it if the array functionality (eg. x8 or /3 etc) was available when guidelines are created.
At the moment you have to create a guideline and then use the move/copy tool to gain this functionality.
It would be faster and more intuitive if these functions were built into the guide line tool.
Examples of how this might work:
Create a guide from and edge and type:
600 x6 or etc to specify the distance and number of copies
Or create a guideline from an edge and set it by picking another edge then type:
/5 to create guidelines at the correct divisions.