I'd have to say Christmas....probably because of all the background stuff in the pictures, and I always feel like I have to make the pics B&W so the pics don't clash with the paper.
I don't think I have a least favorite. If you looked through my albums you would think that all holidays are my least favorite type. I rarely scrap holiday layouts because I sometimes get so caught up in the event I forget to take pictures.
I can knock some Christmas out! It's the birthdays that I have trouble with! Why???
Actually...I go on a 4 day crop retreat about 4x a year. I ALWAYS work on Christmas stuff! They laugh at me, but I'm almost caught up with ALL my Christmas stuff!!