The way I see it is that there are no options that are particularly good. The iPod seems to have a lot of the features, but the cost is too high, and most of the other models that have larger capacities use 2.5" hard drives which are larger than the iPod’s, thus making it impossible for them to beat the iPod’s size.
I suppose your best bet would be to go for Creative’s new Jukebox 3. It’s pretty impressive, considering it has Firewire, USB, 20 GB capacity (possibly more in later versions), 11 or 22 hour battery life (with optional second battery) and a plethora of inputs and outputs. Sounds nice, but of course it’s gonna be big and heavy compared to other models (except the older jukeboxes). Another downside is that the old jukebox had a long load time and poor/slow interface. This should be fixed, but we’ll have to wait till the jukebox 3 is actually out. Lastly, creative’s software isn’t the best.
Personally, I’m gonna wait till there’s a 20 GB, 10+ hour, Firewire enabled, iPod-sized clone available for the PC with a quality interface and software for $3-400. It would be nice to have OGG Vorbis support too. I might have to wait for a while, but that’s fine with me.
On a side note, maybe you might want to look in to using something else like LAME to encode your MP3s. I’m not sure of the quality of RealOne’s encoding, but Real’s software in general seems to be pretty crappy. The encoder makes a difference-192kbps with the Xing encoder sounds much worse than 192 kbps with LAME. Let your ears be the final judge.