Paul,
You need to be a bit more specific about "civil". The current product is Civil 3d 2010. It is not backward compatible with past versions, and requires object enablers to view the proprietary portions (like contours (surfaces), alignments, sections, etc). Now, stepping backwards, there are versions of Civil 3d going back to 2006 and their companion Land Development Companions, and prior to that (2005 back to R14) the Land Development Desktop. Many firms are still using LDD software, and some are in transition to the C3d.
There is a "crippled", less costly version of Civil 3d, Civil 2010, but I doubt that many firms are using it, in preference to either the full civil 3d, or continuing to use the tried & true LDD. It can be "interesting" trying to get these packages to talk to generic acad or revit.
Reid