You should have seen the palmOne announcement of our new LifeDrive mobile manager handheld this week. It's been in the rumor mill for a while, and I enjoyed reading the slightly inaccurant rantings from the Palm OS enthusiast community. The LifeDrive is new technology in the PDA space; it doesn't do everything you'd want it to do the speed isn't as good as I'd like, and I wish the hard drive was at least 20GB, but I already think it is really, really useful in its current configuration.
The LifeDrive works pretty well as an external hard drive for your laptop or desktop system. It's got a FAT32 file system and enough space to store a lot of documents. This tends to change the synchronization paradigm a lot; where before, you had conduits that reformatted or excerpted data between your PC and your device, now you can just have the data in one place -- on the LifeDrive -- and have your PC directly modify that data. This opens up some real opportunities in the application development space for the PDA.
In particular, I'd love to see more applications that can parse and manage data from desktop apps. I use Eudora for my email, and I think it would be really good to see an update to Eudora for Palm OS that works off VFS storage. Eudora already is very portable from PC to PC, and being able to keep the same mail store when I'm mobile would be really, really nice. I could see similar things for PC databases and vertical applications.