It comes as little surprise to see Rockstar Games' Grand Theft Auto IV sitting atop the NPD Group's April software sales chart, with the Xbox 360 version scoring 1.8 million-plus sales alone. Mario Kart Wii, however, keeps GTA IV from total chart domination, as it outsold the PlayStation 3 version by an estimated 120,000 copies. Combined, however, both GTA IV's had a stronger debut month than March's chart topper, Super Smash Bros. Brawl.

Nintendo didn't just have a good month on the hardware side, as Wii games Super Smash Bros. Brawl, Wii Play and Guitar Hero III all landed in the top ten. New Pokemon action helped two DS titles grab pre-break billing.

1. Grand Theft Auto IV (Xbox 360) - 1,850,000
2. Mario Kart Wii (Wii) - 1,120,000
3. Grand Theft Auto IV (PS3) - 1,000,000
4. Wii Play (Wii) - 360,000
5. Super Smash Bros. Brawl (Wii) - 326,000
6. Gran Turismo 5: Prologue (PS3) - 224,000
7. Pokemon Mystery Dungeon: Explorers of Darkness (DS) - 202,000
8. Pokemon Mystery Dungeon: Explorers of Time (DS) - 202,000
9. Guitar Hero III (Wii) - 152,000
10. Call of Duty 4: Modern Warfare (Xbox 360) - 141,000

Total software sales reached $654.7 million for April '08. That's a 68% boost over the previous year, which saw just $389.4 million in software spending. Yeah, just.

NPD analyst Anita Frazier notes that GTA IV saw an attach rate equal to 20% of the total Xbox 360 and PlayStation 3 install base. She also reiterated that next month we may see far more impressive sales of Rockstar's crime epic, but that its April sales were nothing to sneeze at, writing "With only 5 days at retail during the reporting month, GTA IV is one of the fastest-selling titles in video games history."