After HP announced its acquisition of Palm, I think we can be sure that the mid-time future of WebOS seems quite safe. I also expect mechanically much better hardware among the devices they will ship.
However, the acquisition could also mean a shift in politics, i.e. cause the new devices to be locked down with cryptographically signed kernel images. One of the big advantages of the existing Pre and Pixi is that they are not locked down and that as a user you can take full control over the device.
Another policy that might come under re-evaluation is the relationship between the WebOS Application Market and the third-party application installers like Preware.
Lets hope the managers responsible for WebOS future realize that their chance is to be less restrictive and more open than most of the competition - including most Android devices. At least, one could hope, HP has quite some experience with Linux and the Open Source community in other areas of their business.