Series/Franchise milking the most out of people?

 Spoiler

I love it but still, so many:
The Need for Speed (1994)
Need for Speed II (1997)
Need for Speed III: Hot Pursuit (1998)
Need for Speed: High Stakes / Need For Speed Road Challenge (1999)
Need for Speed: Porsche Unleashed (2000)
Need for Speed: Hot Pursuit 2 (2002)
Need for Speed: Underground (2003)
Need for Speed: Underground 2 (2004)
Need for Speed: Most Wanted (2005)
Need for Speed: Carbon (2006)
Need for Speed: ProStreet (2007)
Need for Speed: Undercover (2008)
Need for Speed: Shift (2009)

[COLOR="Red"]NFS has a lot of games, but I'm glad you put the years in them...

 GH Games

[COLOR="Red"]Gutiar Hero (2005)
Guitar Hero 2 (2006)
Guitar Hero Encore: Rocks the 80's (2007)
Guitar Hero 3: Legends of Rock (2007)
Guitar Hero: On Tour (2008)
Guitar Hero: Aerosmith (2008)
Guitar Hero: World Tour (2008)
Guitar Hero: On Tour: Decades (2008)
Guitar Hero: Metallica (2009)
Guitar Hero: Modern Hits (2009)
Guitar Hero: Smash Hits (2009)
Guitar Hero 5 (2009)

Coming November-ish: Guitar Hero: Van Halen (will be 2009)[/COLOR]

Side note: Am I the only one who thinks Activision's numbering system is wonky as fuck...? Guitar Hero 3 is the fourth game, there is no Guitar Hero 4, and Guitar Hero 5 is technically the 12th game, 9th on consoles.[/COLOR]