Cowon iAudio players beat everything else, but they are also quite expensive (not quite as expensive as the average iPod, but still). I'd say the D2 is a good option, it provides SD storage as well but has a better screen and better codec support compared to Creative's players (FLAC! Yes!). It has a touch screen and recently even started supporting Flash Lite!
Personally, I own a Zen V Plus 4GB, but that's just an in between thing until 32GB (or preferably even higher capacity) flash players start coming out from iAudio.
The main drawback for my player (that Zen V Plus) is that you actually do need extra software, it doesn't support UMS. MTP is teh suck... I just use Winamp for now, but I still don't like it. I organise my own music folders, I don't even need that crappy ID3 navigation.
BTW all players that use MTP do the same thing as the iPod does: the player's database gets updated by the host computer during song transfer, it's not the player itself that does that.
I don't know whether the ZEN uses MTP only, but if it does, I can't recommend it. It does have the looks, though
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