Some time ago I asked you guys, if you had a good advice for a good mp3 phone. As you didn't really help me (hehe!) I bought a Motorola Rokr E2.
And is amazing. I love it. IT has 1GB SD (pretty standard), FM radio, 3.5mm audiphone plug, it charges via an standard mini usb cable or AC to usb converter. Compatibility all the way.
But it's killer feature to me is Linux and java. It has a linux based system and an java interface. Is hackeable as much as you want. Usually motorola phones are pretty much customizable, but his one blow everyone else away. You can use the phone with the pc as a modem, as a storage device and as a network node. You can telnet and get a shell. It has samba installed by default. With a little of effort you can even get a shell in the phone. Most of its configuration (being linux) is just plain text file which you can edit with vi. You also can install java apps, or linux apps.
I think those motorola guys used the E2 as an experiment, to see how the geeks (the ones who will use the most hardcore features) reacted, because there will be serious competition via the iPhone and the OpenMoko (I think that is it's name, also a linux phone). What makes me think that? The root shell has no password :). It has "hack me" painted all over it.
I love that phone. I haven't had a single problem with it after two months.