Valid photo identification is required for the things that follow:

adopt a pet
purchase a home
purchase an automobile
purchase a gun
voter fraud
obtain a bank account
obtain a credit card
obtain a passport
write a check
make a credit card purchase
apply for a loan to purchase anything
to prove your age
to get married
to receive a marriage license
to drive
to buy a house
to close on a house
to get medical care
to get on a plane
to get insurance on anything
to get a job
to get a post office box
to get a hunting license
to get a fishing license
to get a business license
to cash a paycheck
rent an apartment
rent a hotel room
rent a car
rent furniture
rent tools and equipment
receive welfare
receive social security
receive food stamps
buy cigarettes
buy alcohol
buy a bus ticket
buy a cell phone
buy any antihistimine
go in to a casino
go in to a bar
go to college
have your water turned on
have your electricity turned on
have your cable turned on
have your gas turned on
obtain trash pick up service
pick up a package from the post office
pick up a package from fed ex
pick up a package from ups
pick up a prescription

Things you do not have to have ID for:

Vote.