I swear every time you make one of these topics I instantly have an incredibly childish reply in mind. I'll keep it to myself this time, in an attempt not to embarrass myself any further than I already have.
One pillow is the properly proper amount of pillows, although I used to sleep with two. Now, blankets on the other hand...I would check excessive amount despite only usually sleeping with between 2-5 depending on time of year and if my father is into heating the house or not. But I keep about ten on hand just in case. (I like having options.)
two billows are the minimum required for comfiness, and it depends on the type of pillow. i need a body pillow to wrap myself around, then another pillow to rest my head -- i prefer to have two pillows to arch my neck.
I've been using just one lately, but I generally find that I sleep more comfortably with two pillows under my head.
Although it also depends on the softness of the pillows. The reason I use two is to keep my head slightly elevated, so if I have one thick really firm pillow, that tends to do the trick. Likewise, pillows that are ridiculously soft, such as most hotel pillows, which your head just sinks right into, I tend to have a hard time sleeping with. So, for all intents and purposes, given average size and softness, two pillows under my head does the trick.
There is no such thing as too many pillows. Some people i could mention (@Jamie ) sleep with one ****ing concrete slab flat thing which murders your neck and thinks that is totally acceptable. No. I need 2-3 in a perfect world at least.
I have 9 pillows in which I lay out across the mattress. Two more pillows are used for my head which are aligned perpendicular to each other. Then I have 2 pillows between my legs, one under my arms and a body pillow on each side of me. I then have 3 pillows put on top of me by my mother and have her tuck me in tightly so none of them shift around. It's a very delicate process that if ruined will have me wake up in the night screaming.