I think the ipod is a good source for the pa2v2, especially if you use the line out instead of the headphone jack. I’ve tried many mp3 players over the years I think the ipod gives the best sound to date.
As for which Ipod I’m not sure what to advise you, I’ve got the classic but maybe the others mp3 players are just as good. For that it might be worth having a look on a couple of review sites to see what other users think.
MP3 Player : Reviews, Prices, Comparative guides and Buy Online
By the way, for the headphones, if you want to replace your portapros go for the PX100’s
Sennheiser PX100 Review they have a tighter bass and much smoother hights than the SR60’s.
Let me know what you think