The Simpsons
The X-Files
The Practice
Gideon's Crossing
The West Wing
The Beast
Gilmore Girls
Charmed
ER
Nash Bridges
The Lone Gunmen
The Tonight Show with Jay Leno
I found that the most violent show (of those listed above) is "Nash Bridges", closely followed by "The X-Files". (Note: "Nash Bridges" was cancelled this season due to low ratings.) The most violent commercial I found was a promo for the new movie "Tomb Raider", starring Angelina Jolie.