I recently found out there is a way to bring some life into my aging iRiver H120. I had installed Rockbox for a long time for its FLAC support, and the guys from Rockbox found a way to enable the use of CompactFlash cards as internal storage. This has the advantage of getting bigger storage (currently 64GB CF cards are available) at a lower weight, no noise/clicking as there are no moving parts, better response times as the CF card does not need to park heads or stop/start spinning and of course lower power consumption and prolonged battery life.
I decided to get a Transcend 32GB 133x card, as those are the cheapest 32GB 133x cards available and have real solid performance (as reported by various users on Am@zon.de). Additionally they offer life-time guarantee.
I followed those two guidelines:
http://www.rockbox.org/wiki/CFModGuide
http://www.anythingbutipod.com/forum/showthread.php?t=45252