i'm using a transcluent teal Rio500 w/ latest firmware and a 64MB flash card for 128MB total memory...
the decoder is one of the best in portable players, it has backlight, equilizer, uses one AA battery and is one of the smaller but nicer looking mp3 players..
another good on is the sensory science rave mp 2000 (they may have better ones out now), tho it lacked a backlight so i went w/ the rio500...
don't get the sensory science clik disc ones...they suck...simply because they use 40mb iomega clik discs...they're larger, they drain your batteries faster and can skip (due to moving parts - relevant to battery draining and skipping)
damn, i just love my mp3 player...the rioport software sucks tho, so i use real jukebox which supports the rio500 and si good (drag n' drop from explorer to realjukebox)