Thanks for the responses so far, I take it I need to use the 'Definition Query' function in Properties when right clicking on the contour layer? :)
I would use the definition query. Just make it simple and use a wildcard like function for contours ending in 0 (zero)
[Elevation-Field] like '%0' or [Elevation-Field] like '*0'
whatever your elevation field is. This will look for all the contours that end in 0 or whatever number you put in there.
The % sign and the * are wild cards. * works for geodatabases and % works for shapefiles and or SDE I forget which. If one does not work try the other.,