First and foremost:
Rachel, Monica, Phoebe, Joey, Chandler & Ross from Friends.
Their death should be so horrid that they couldn't even live in syndication.

Diane Chambers from Cheers - she grates on my nerves like scratching a chalkboard.

the Dawson's Creek Kids - need you ask... Especially Dawson (Van der Beek) - would like to see Gallahger smash his huge head like a watermelon

thinking about it - Gallahger himself

any and everyone in those 1-800-collect/CALL-ATT commercials just for making them -
especially CarrotTop - he should die in a prop mishap

these are just the first few that come to mind....