Based on the Top Selling PC Games for March 2006, it really looks like it.
1. The Sims 2 Open For Business Expansion Pack
2. Elder Scrolls 4: Oblivion
3. Star Wars: Empire At War
4. Dungeons & Dragons Online: Stormreach
5. Lord of the Rings: Battle For Middle Earth II
6. World Of Warcraft
7. The Sims 2
8. Elder Scrolls 4: Oblivion Collectors Ed
9. Lord of the Rings: Battle For Middle Earth II Collectors Ed
10. MS Age Of Empires III
13. Battlefield 2
*List is based on units sold by more than 70 channel partners, representing 90% of the U.S. retail consumer market.