Plan Sets

I work for a civil engineering company where we produce plan sets of
sites consisting of ...Existing Conditions Plan, Layout Plan, Grading
Plan, Drainage Plan, Utilty Plan..etc. This can be up to 12 different
depictions of the same site. We typically accomplish this in ACAD 2005
by saving layer states for these different desired sheets, and use a
single layout tab with the titleblock changing with the layer state
change. To Plot we change the layer state then plot the layout. When
the site is very large (ex. 10 acres or more) we add more layout tabs
to cover all the geographic area.

We are now upgrading to acad 2008 and I wonder if we should change our
practice. With the new addition of layer states being able to be saved
within layout tabs should our layout tabs now be plan sheet specific
as opposed to geographic specific. How do you folks cover a large
geographic area with multiple depictions needed and why?

Thanks,
John B.