Even though I knew in theory that clairvoyance and value list controls in FileMaker 8 were cool, it wasn't until I started tinkering with my address entry fields in Studio Manager that I found out how cool.
The thing about address fields is that everyone has them. Which of those fields can benefit from clairvoyance and list controls? I experimented with it and submitted my findings on my Studio Manager Bulletin blog. These checkbox features are just the kind of thing my clients can implement for themselves.
I'm sure you couldn't justify putting a value list on the zip code field in a lot of situations. But in a place where most business comes from just a few zip codes like in a major city, this might have some value.
By the way, the arrows and clairvoyance disappear seamlessly when you access the file using FileMaker 7. These 2 features are 7-Safe.