I got a couple of vintage Sony Discmans recently. First was the D-5A; I think that's either the first or second Discman ever made. Sounds really nice; it even has RCA out. Then, I got the D-311. This is apparently a legendary vintage portable and often fetches pretty high prices on eBay. I haven't had time to properly test the same music on vinyl, discman, and FLAC; but that's one of the eventual goals. For now, I'm using the D-311 and it sounds slightly better than a FLAC rip.
I also got a chance to upgrade my setup at the office recently. Before, I was using a pair of Etymotic ER-6i with the output from my Powerbook. I also tried it with a portable amp (PA2V2) but that didn't seem to make a huge difference. I attribute that to the bad source (ie, Powerbook). So, a couple of weeks ago, I got a portable DAC, the Firestone Fubar II. I also upgraded to the Eytmotic ER-4p. So now, the chain is:
Powerbook --> (via USB) Fubar II --> Zu Pivot --> PA2V2 --> Etymotic ER-4p
I also got the 4p-4s converter to make the ER-4p into ER-4s. Haven't actually tried that though. Maybe in the next couple of days. But so far, it sounds great. The 4p has much better bass than the 6i, and also a better seal. The DAC just makes everything better than the crummy Powerbook audio out.