Interesting read, thanks. Audio is one of the few areas I still occasionally see Linux desktop glitches too. I’m not doing anything as complex as yourself, recording wise, but once in a while some app or other seems to not yield audio control back to the system. Admittedly, I can’t recall that that’s happened since I clean-installed 10.04.
WRT the portable media players, I revived my wife’s iPod video (30GB I think) with an installation of Rockbox, whiich is very Linux Friendly. When I did so I inherited her old iRiver H10 (6GB) player, which I now use, also with Rockbox, although almost exclusively for podcasts. It does support FLSAC though, which is nice for the occasionaly time when I do want to do some serious music listening. It works great with gPodder on my Ubuntu desktop box.
It may be worth having a look at Rockbox, I believe they’ve added support for a few more iPods in recent times.