Charlie and Lola and Peppa Pig. Why? Well, Charlie and Lola is just silly and cute and told from such a childlike perspective.
Peppa Pig is SHORT which gives is HEAPS of point from me (lol) and I also find it highly amusing when they snort and fall down on their backs snorting and laughing.
I also love the theme song to Olivia and Small Potatoes... I sing them both quite loudly.
My all time fave kids show ever from the ABC though is Pingu. Pingu is such a jerk... but he's so funny when he slaps his little brother about. I just adore Pingu.