I know it was a while ago, but Clefairy doll?! hell what I'd do for Clefairy doll now, especially since fossils gives prizes now. That Rayquazza isnt the worst^ the fire type one is terrible, but suuuch nice artwork. Bad cards don't bother me too much, unless they're rare! arg! I hate it when you get something like Purugly as the rare in the pack, what a waste.
OK, now totally on-topic the worst card (in play atm and compared to rarity) I think is... Charizard PK. It's hard to say "ever" cos' some of the best things from the early sets, just look awful now.