Halb, thanks for the impressions so far. My listening is pretty evenly divided between classical and pop/rock. I'm encouraged by your impression that the RS220 is good with classical, but I'm curious why you think they might not be the best choice for pop and rock.
Also, according to the manual, the RS220 modulation is 16-bit at 48kHz, so I would think no matter what source you use, you will ultimately be limited to 48kHz, since ultimately everything you listen to will be transmitted in 16/48. That will probably be the next step in wireless cans - upping the modulation to 24/96 or 24/192, so they can reproduce hi-res signals. Personally, I'm content with 16/48, since virtually all of my listening will be off of CD or iPod, but it would seem the RS220 isn't totally future-proofed.
Betavince, from one newbie to another, welcome to Head-Fi.