Davydenko (mean-spirited, said nasty stuff about Roger, Rafa and his own wife)
Verdasco (should be called "Piggy" rather than Nadal for his spitting on court when he lost to Rafa)
Tomic and Harrison (spoiled brats)
Monfils (arrogant and clownish)
Stepanek (in your face)
Almagro (strange and unpredictable temper tantrums)
Nastase and Tiriac (just plain nuts)
Someone can't count pretty clear in the first post it's 10 votes. Just counting for the first 10, honourable mentions are allowed.