if you want a large screen, at the moment there are the new Onyx Boox M90 and the Pocketbook 903 (ok, there is the Kindle DX, but from what I udnerstand the consensus is that it does not handle pdf well - plus it handles fewer formats than the other two). The first one has a pearl screen, the second one doesn't but still the display is good. There is a video comparison of these two devices
here, however if you are itnerested I woudl urge you to at least lurk (if you do not want to ask questions) in both forums, as you will get a better idea. For instance, the Onyx does read mp3 files, but I am not sure whether there is a proper mp3 player there (you have it in the PB903). For both devices the touch interface is via astylus, not your fingers. Neither device is quite there yet, but if you are not in a hurry you can wait a couple more months to see how things pan out.
The Asus DR900 is also 9.7'', but has a Sipix screen that many find too dark. But again, have a look at the
video and read through teh relevant threads here on mobileread (eg
this one).
If you are fine with a smaller screen (and I have to say I can read very well pdf files on my 5'' Pocketbook 360, though of course I prefer the larger device), you may have a look at the smaller "brothers" of the two devices above, i.e. the Pocketbook 603 and the Boox A60. Another 6'' device that has mp3 player, and this time with a finger touch interface is the Pocketbook 302. But when it comes to 6'' devices there are many out there, you may want start narrowing down your choice by looking at
the famous Mobileread matrix.