I would really like to carry one device. Ideally this would be the Palm Pre: phone, email, sms, internet, calendar, contacts, and media player. I listen to a lot of podcasts and music on my 30GB iPod classic right now, and it would be great to not carry it around anymore since I have the Pre.
The good news is that the Pre takes a standard headphone plug so I could use my favorite earbuds. The reason I never tried to use my T-Mobile Dash as a music player was it required a mini USB connection. Also in the plus column is the iTunes syncing capability. When I connect the Pre to my PC, I'm given a choice of "Media Sync", "USB drive", or "Just Charge". Media Sync will open iTunes and I can select playlists to sync to the Pre just like I do with my iPod, or I could use it as a drive to drag and drop files to and from.
I'm not much of an audiophile. I can't hear any difference between different bitrates. The Pre sounds pretty good to me, but my problems are with the controls. This is why I won't be giving up my iPod anytime soon: I can't use the player controls with one hand and I end up hitting the touchscreen accidentally very often.
With the music player, if you are in album view, you pause the song when you tap the screen. That's pretty easy to do unintentionally. If you are in list view, the accidental tap will start a new song. In the video player, fast forwarding or rewinding is awkward with the small slider, but at least it doesn't skip ahead if you tap the screen (it will just toggle the controls into view).
I'm still hoping to reduce my media player mode load down to one some day, so maybe there's an app in my future.