These are just some of the modern essentials we don't own and we manage to live a close approximation of a 21st Century life:
car (I can't even drive!)
food processor or anything similar
bath (we only have room for a shower)
hairdrier or any kind of hair styling paraphenalia
We do own:
a computer with printer
a radio/cassette/record/CD player
a tv, video player and DVD player (the tv and video are old)
a fridge, washing machine and cooker
an iron, but we don't use it very often.....
2 alarm clocks
too many books
What do you not own that people would expect you to own? What do you own but you could consider giving up to reduce your impact on the environment?