I'm sorry about the long wait. I've been rearranging this list because I've replaced one game with another and refined the actual countdown itself. I apologize.
Where would the music game genre be without Rock Band? Since it's debut in late 2007, just about every music game has mimicked it one more ways than one.
The biggest way obviously is the peripherals. Before Rock Band, music games focused on a single discipline. Dance Dance Revolution focused on dancing, Guitar Hero focused on the guitar and Karaoke Revolution was all about singing. Rock Band took all these elements and combined them into a complete package. Each player contributed their part, and it felt like everyone was a part of a band. And it was a bigger hit at parties than DDR or Guitar Hero ever were.
That's the obvious point, another reason why Rock Band is so influential is its use of downloadable content. Every week Harmonix puts out a few packs of music for you to download and play, essentially making Rock Band an interactive iTunes. Since Rock Band, music games have been practically required to include after-market content. Guitar Hero tried a different approach to counter Rock Band's structure by releasing droves of games in a short period of time with disastrous results. Harmonix has treated Rock Band like a platform for players to build their personal library from, and it works. Other games like DJ Hero, Rock Revolution, Lips and Def Jam Rapstar have released DLC to expand their shelf life.
Notable games influenced by Rock Band
Every Guitar Hero game since Guitar Hero: World Tour (several dozens)
Numerous "off-brand" imitators (Rock Revolution)
Just about every music game since Rock Band bears its influence. Even Guitar Hero, which was around a few years before Rock Band and had a larger following, followed in its footsteps by expanding into a fell-band game. There have been many "off-brand" (off-band?) games that tried, and failed, to cash-in on Rock Band's success. There are too many for me to list above, but they have all followed the full band formula debuted by Rock Band. DJ Hero was successful because Activision knew that there was 1) a market for peripheral-based music games and 2) an untapped mainstream market in electronica/house music since Rock Band already had Rock 'n' Roll games cornered. And Lips has a steady stream of DLC much like RB's model.
Many people are burned-out on music games right now (Thanks Activision). But with Rock Band 3 coming out the end of this month and all the new stuff Harmonix is doing with it (keyboards, pro-mode etc.), they may just re-ignite people's interest. Guitar Hero may have paved the way last-gen, but Rock Band was the pinnacle of the genre and that is why I've made it #7 in the 10 most influential games this generation.
LOOK WHO CAME: