Margaret, I keep rats... I certainly am not one to criticize anyone else's pet choice
I have a lot of respect for spiders and the role they play in the ecosystem (whether that is a natural place, my garden, or even in the house). I just like my pets to be warm and fuzzy and pettable, so I stick with mammals. I put spiders in the same category as fish and reptiles when it comes to pets... just fine, but not for me.