When December video games sales results are released - expected after the market closes on Jan. 14 - Wedbush Securities analyst Michael Pachter forecasts a 12% drop in sales over the previous year. Driving the majority of that fall-a full two-thirds-is a continued lag in music game sales, to $250 million from $468 million in December of 2008.

"After two consecutive phenomenal years of growth, with software sales up 34% and 27% in 2007 and 2008 respectively, the videogame software business showed signs of vulnerability, with a precipitous decline in music category [sales]... likely due to saturation for the music genre," Pachter said.

Overall, he expects sales for music-based games to finish the year 50% below 2008 levels. And of the games expected to spark a rebound-Splinter Cell Conviction, BioShock 2, Singularity, Dante's Inferno, etc-none are music titles.