Though they wouldn't let me take pictures of the experience, I just got a first chance to handle the Palm Pre, and I can tell you it's the ultimate stealth handset.
It transcends what a mobile device should feel like. It's smooth but also tough enough to feel like you're using something that's going to last. I really like how the back of the slider is reflective like an iPod touch (might be good for the ladies and their make-up too).
The display looks richer in colour gamut than any handset I've ever seen (almost like a mini Cinema Display). The GUI seems fluid enough so that it's not overtly cheesy and plasticky looking (transitions are still rough around the edges sometimes and not always as snappy as you'd like.) Speakerphone seems more than adequate for being Monophonic (totally usable for listening to music/calls.)
This is just like OS X, Expose, Spaces, Spotlight—uninterrupted multitasking. Even the cal is like iCal—on the desktop OS. When you get a call, the OS puts what you're doing down at the bottom, instead of dumping it like on iPhone. [Palm Pre Details]