I think milking is either annual releases, re-used assets or just slapping a name on something and calling it a day.
So, COD is milked, AC is being milked and Guitar Hero was milked till it died. Final Fantasy milked FFXIII by making little-effort sequels, kind of like X and X-2. Mario as a character is milked by throwing his name on Mario Golf, Mario Soccer, Mario Mario... His games aren't milked though. I actually wish they made more 2D and 3D Mario games.. 1 or 2 per generation isn't enough. Same with Zelda. Just stop the side branding. There was a time when Nintendo made NHL Hockey or K.Griffey Baseball. Now it's just Mario everything.
Games that put out a sequel every 2 or 3 years isn't milking. GTA, Uncharted, GoW, Halo, NSMB, 3DMario, Zelda, GT, ... why not have these games every so often. They're great. I like a healthy dose of stuff I like every now and then.
The worst offenders are probably EA's sports games. Usually the only thing your getting for your money is a roster update. Pretty weak.
