Not A favorite, but several:
P90X SHoulders and Arms (pretty much ALL the P90 X weight workouts, but this one stands out), "Plyo X," "Ab Ripper X," "Core Synergistics"
P90 Masters "Sculpt 5-6"
Power Half Hour (Tony Horton) "Arm Toner" (full upper body workout)
Jari Love's "Get Ripped to the Core"
Kelley Coffey-Meyer's "Shape of Things to Come" and "Get Ready, Step, Go"
Kimberley Spreen's "Cardio Camp"
Amy Bento's "A-Team Bootcamp"
Mindy Mylrea's "All About Abs" and "All about Legs' (segments as add-ons) and "Kick Butt Bootcamp"
TLT's "Finding Your Core" and "Strength in Movement"
Powerstrike Millenium I, II and III
Gin Miller "Intense Moves"
Eoin Finn's "Power Yoga for Happiness" (especially the "magically hips" workout)
Debbie Siebers' Slim Series "Firm it Up"