The video games, consoles and game accessories market took in $1.12 billion in U.S. retail sales in May, an increase of 37 percent over the same period a year ago, according to figures from NPD Research.

Despite its top position, Grand Theft Auto IV isn't having as much of an impact on hardware sales as expected for PlayStation3 or the Xbox 360 games consoles.

"The continued success of GTA IV is not translating into big hardware sales for either the PS3 or the 360 but there may yet to be a lift in June due to gift-giving for Father's Day and Graduations," said NPD analyst Anita Frazier in the report.

Instead, Nintendo Wii is ruling the sales of the next-generation gaming consoles with 675,100 units sold in May. In second place, Nintendo DS sold 452,600 units for the fourth consecutive month. The PlayStation Portable fell into last place, with 182,300 units sold. The much ballyhooed Wii Guitar Hero III: Legends of Rock with Wire sold 116,800 units in May and Nintendo's DS Pokeman Mystery Dungeon: Explores of Time sold 102,000 units.

"A lot of folks are interested in the battle of the bands," said Frazier. Year-to-date, Guitar Hero III has sold 2.5 million units compared to Rock Band's 1.3 million which lands them both in the top 10 titles for the year so far."