Wow, this old thread still alive
. Recently someone reported that the Cowon D2 can accept SDXC cards if you format them to FAT32. So you can put a 128GB card into a D2. I think I'd just get that and call it a day. The 128gb cards cost around $170 and I figure that 256gb cards will be arriving soon (since they now have 64gb micro cards, and the full size card is about 4x as large physically). The 64gb microsdxc's are currently $135 so still much higher $/gb than a 32gb card or a full sized 64gb, but if you are flush you can use one in a Sansa Clip+/Fuze or Cowon C2/J3/whatever. These all have good SQ.
The Archos 48 (500gb Android 1.6 player) is discontinued but adorama.com still has some around $200. I'm slightly tempted because I figure once they're gone, nothing like that will be made any more. I think it uses a laptop sata drive so you can upgrade it to 1TB. SQ is supposedly not too bad, but maybe not as good as Cowon or Sansa. There is also the Cowon x7 which is a 160gb hard drive player that's gotten some favorable comments, though it's kind of big and expensive for my tastes (I'd want a hd player to have 500gb or more). The Archos also has a USB host port so there's a chance you could set it up with an external DAC/amp, giving you an ultra capacity audiophile rig that's still reasonably portable.
Using any type of handheld electronics while driving a car is apparently illegal here in California and you can get a ticket for it. I guess I can sort of understand that it takes more cognitive effort to operate something that's not on a fixed mount of some sort. I bought an in-dash player with an aux input a while back but I find I never use the feature, so I'd go for a pure in-dash player for car use now. There are probably some that play flac.
I've used car FM transmitters a few times and they just totally suck, especially in urban areas (strong broadcast signals and no empty channels). They might be useful in some last ditch situations when it's someone else's car and you're out in the boonies, but if you're setting up your own system it's far better to avoid. Bluetooth ad2p is probably ok but I haven't tried it.
The hifiman player got pretty bad comments on ABI, apparently it's not that great an audiophile device, more of a high-$$$ gizmo for its own sake. There's a new comparable unit from iBasso that sounds like a hifiman "done right" though comparably expensive (way out of my range so I didn't pay close attention). I'm not convinced 24 bit is worth it for portable use.
