Lower sales?
Mario Party
'Hero' franchise
Sonic
Need for speed
on a personal note: yearly sports games

Mario Party 8's the best selling in the series actually.  Mario Party DS is the 2nd best.

All the others (Hero, Sonic, NFS) are way down though, and most annual sports games are down too (except Tiger and FIFA).

Ratchet
Singstar
Guitar Hero
Call of Duty
Final Fantasy [The spin-offs]
Most sports series

If Mario isn't milked than neither is Final Fantasy.

SingStar can't really be called milked because they cater to all the different taste's people have in music.

Halo isn't milked, yet. But it's well on its way. It's only 6 releases in 10 years, but you have to consider 3 of those releases were in a timespan of 7 years and the other 3 are in a timespan of 2 years.

Mario and sport games
Not Halo at all a main game every 3 years isn't milked at all.

Then how is mario milked? Mario 64 (1996) Sunshine (2002) Galaxy (2007). That's a main game every 5 - 6 years...

- Guitar hero is the perfect example.

- CoD is up there

- Mario Party to an extent.

- SingStar

- Ratchet

- Sports games, but it's been like that forever.

has to be guitar hero. i mean seriously.. how many titles can you release?? i can see how people would get annoyed with madden every year... i think they should just release a good product once in a while.. and then release DLC that supports. seems reasonable

God Of War with 6 different versions in 6 years. It has come onto milking

mario
mario kart
zelda
sonic
guitar hero

True.

looking at the sales for the entire series one could see that it's only in this gen the sales picked back up...because of the extended userbase and the hope that the wiimote/DS would make it more interesting.