iPod: Lossless vs 320 vs 192

I'd like to hear from folks that have compared lossless on an iPod to some of the higher lossy bit rates like 320 or 192. Now that iPod comes in 160gig, this reopens the question for me: Should I bother carrying the heavier unit (rather than a nano) in order to hear lossless (vs my current 192).

Target application is an iPod, not a high end stereo, BUT, I use the best in-ear phones (currently Westone UM2, soon either Westone 3 or Shure SE530). So subtle difference are audible, but soundstaging is not such a big deal.

So, do any of you have experiences to share on this front?

Of course, stories of your experimentation playing on higher end systems are interesting as well, but my own inquiry right now is:

Will I hear a marked difference playing my iPod on high end earphones, between, 192-320 formats and the lossless format?

Thanks!
Art

ps: Another complicating factor is that I think the larger iPods generally have somewhat better sound quality, richer, stronger, than the tiny second generation nano. Sigh. Decisions.....