Now we're starting to see some really cool apps and fewer "me too" types... such as those who joined in the deluge of Yelp-driven restaurant reviews and tip calculators.
Simplify Media: wirelessly access your whole iTunes library and playlists. Personally I think this should be built in, along with the Artist info and Lyrics capabilities. No longer is the tradeoff between cool device (iPhone/Touch) and having all your music (Classic) needed. You can keep as much as you want on your smaller capacity device and just stream the rest of them from your computer. Yes. This quite simply a media sever, but the best part is how easy it is to set up and quietly it runs on your computer, in terms of memory usage. It's great for singing along to your music without having to go to a lyrics site, search, and open up the song you want too. I keep it right next to the Remote app, first page.
AirSharing: I'm still trying to work with this one, since they haven't built Vista 64 bit support yet. Vista support is getting much better though with the upcoming 1.0.1 release. Updates later, but in short it lets you use your Touch or iPhone as a wireless USB drive. You mount it on your computer and you can transfer files back and forth and open up any of the recognizable formats (documents, presentations, spreadsheets, PDF) on the go, offline. Of course you can put other files on it as well, but not for viewing. I find myself using it for the openable formats, but not for others (since I carry a 2GB flash drive with me on my keys).