I have a Zen X-Fi 16Gb flash-based player and I'm very happy with it. Battery life is excellent, sound quality is excellent, user interface is OK. Video playback is even pretty good. I didn't buy it for video but I watched a couple of feature films on a flight once just for sh1ts and giggles and I was surprised how good it was.
The wireless LAN functionality is a bit wasted. Seems mostly to allow teenagers to social network using some cryptic way of entering text using 9 buttons. Don't expect it to do anything useful like transfer music files.
Software that's bundled with any player is pretty ropey, TBH. At least you don't have to use GayTunes. I wouldn't use it to rip / encode CDs. There is a windows explorer drag-and-drop interface that means I can just dump the files onto the device without ever having to launch the bundled software.
I keep all my collection in FLAC these days and just use a shell script to rip through the whole lot converting it to MP3 at whatever bit rate I fancy.
Not sure I'd bother with a hard drive player. Flash players are getting big enough that you don't need to worry about fragile mechanical bits and the high power consumption that comes with them IMHO.
Kevin