At least 1.8 million copies of Left 4 Dead have been sold at retail since launch (on both 360 & PC) (but we'd love to see the digital download figures instead).

Because hot on the heels of new product or DLC announcements this week, the game has returned to the #1 spot on Steam's charts. It's even experiencing a retail renaissance of sorts, climbing to #4 on NPD's shopfront charts. Were the game available on Direct2Drive, it'd probably be near the top on that, too.

NPD Sales Charts January 25-31 (via Shacknews)

1. World Of Warcraft: Wrath of the Lich King
2. The Sims 2 Double Deluxe
3. Spore
4. Left 4 Dead
5. World Of Warcraft Battle Chest
6. Fallout 3
7. World Of Warcraft
8. The Sims 2 Apartment Life
9. Civilization IV
10. Call Of Duty: World At War

Steam Sales Charts As Of February 11

1. Left 4 Dead
2. FEAR 2
3. Counter-Strike Source
4. Fallout 3
5. Call Of Duty: World At War
6. The Orange Box
7. Dawn Of War II (pre-sale)
8. Team Fortress 2
9. Grand Theft Auto IV
10. Counter-Strike

Direct2Drive Charts As of February 11

1. FEAR 2
2. Rome: Total War
3. Dawn Of War II (pre-sale)
4. Red Alert 3
5. Defense Grid
6. Fallout 3
7. Call of Duty World At War
8. Final Fantasy XI
9. Civilization IV
10. Vampire: The Masquerade

via Kotaku, thanks.