Not everyone who voted on Tuesday cast a vote for every office. This kind of undervoting is described in Professor Sabato's reports on Virginia voting as "ballot fall-off." In his 2001 report (which can be downloaded here from the Center for Politics website), he had this summary of ballot fall-off in Virginia elections, stated as the percentage of all voters who voted in a particular race.
1977 - Governor, 98.5; Lt. Gov., 94.7; AG, 90.8
1981 - Governor, 98.8; Lt. Gov., 94.2; AG, 93.2
1985 - Governor, 97.5; Lt. Gov., 95.9; AG, 96.3
1989 - Governor, 98.2; Lt. Gov., 94.8; AG, 95.2
1993 - Governor, 98.7; Lt. Gov., 95.7; AG, 94.0
1997 - Governor, 98.4; Lt. Gov., 94.9; AG, 94.0
2001 - Governor, 99.0; Lt. Gov., 96.5; AG, 94.7
From this morning's numbers, it appears that in 2005 there were roughly 40,000 more votes cast in the Governor's race than the Attorney General's race, and roughly 4,000 more votes cast in the Attorney General's race than in the Lieutenant Governor's race.