1. Any sort of innocence, especially that childish innocence where the world seems perfect because you're sheltered from all the horrific things until you reach a certain age.
2. Seeing a movie at the cinema. With movies starting to be released on DVD and on the internet at the same time as in the cinema it's only a matter of time before the whole cinema scene is fazed out. It's been going downhill since at least the 50s.
3. Independent businesses. I'm not gonna say anything otherwise this will turn into a long diatribe about how companies like Walmart, Apple and Microsoft are bleeding the planet dry of any kind of charm.
4. A sense of unity and community. Party fits in with number 3, partly to do with the fact that everybody is shit scared of everybody else nowdays. Not helped when you're constantly bombarded with news stories about people killing each other over nothing.
5. Antiques. In 100 years there will be nothing that was made in the year 2000 that is worth it's weight in anything other than shit. Ikea is at least partly responsible for this one.
I can think of more but it's 3AM and my brain hurts. Maybe I'll come back tomorrow.