Hi Keith,
I always use the floor to make odd shaped counter tops also. For sloping drives, if the terrain dies not slope, I use the Ramp (in Stairs), for raked ceilings I just use Ceilings and for many sloping items that are rectangular, I use the Custom Member in Interior Accesories / Decorative - it can be rotated to any angke very easily. I get lost with Surfaces!

I agree that different line styles for Surfaces is a good idea though.
Allan