Once you are using Zones to establish where to look on a drawing for critical dims, you can then use another symbol in the DIM to ID which ones are critical quickly. If these are inspection points, you can use the ovals as well.

__________________
Matt
CAD Engineer/ECN Analyst
SolidWorks 2007
Lorono's SolidWorks Resources
Solidworks Legion blog
Co-moderator of SolidWorks Yahoo! Group