strongm:
The way I usually explain it is this.
If you need a full remote desktop, then Windows Terminal Services is sufficient.
However, if you only want to publish one app, XenApps is the way. You don't have the overhead of the whole windows desktop running, and you can specifically publish the app to the user that you want them to use.
I'm not familiar with RemoteApps; if it's similar, then great. But if it loads a whole desktop, then XenApps is still the way to go.
You can, of course, give a user a whole desktop with XenApps as well. XenApps is also pretty good at load balancing over multiple servers.
Just my $.02
"What the captain doesn't realize is that we've secretly replaced his Dilithium Crystals with new Folger's Crystals."
--Greg