I like both but it depends.
If they're slim then I like a nice round (not necessarily BIG, just bubble-shaped) ass with a tiny waist and great hips (yes, slim girls can have this figure too) and if they got huge tits, that's a plus. I'm a fan of the skinny girl with huge boobs look. It's just fascinating to me personally.
I don't like skinny chicks with ironing-board asses and toddler titties.
As for thick women now, we gotta be honest and state the fact that there's a difference between "thick" and FAT.
I love me a thick girl with nice thighs, a fat round ass, nice hip to waist ratio and if she has amazing tits to add too, that's a plus.
I don't like bellies so huge that they look pregnant all the time and flabby ass bodies that droop all over the place.