Thanks for the input guys. I've switched to the DocumentActivated event, and it seems to be behaving properly. Interesting note, the DocumentActivated event also appears to fire when an autosave happens, and when it does, the MdiActiveDocument.name is the autosave file (*.sv$)
Jeff, that's an interesting problem you were having with MdiActiveDocument. I haven't noticed this issue, but I have had some recent eNotFromThisDocument errors that might be caused from it.