I own the AT ESW10JPN, they are beautiful to look at as well as listen to. I tend to listen to them via my USB DAC/AMP (Predator) as the sound from the amp is better than from the headphone out of my laptop.(mainly a difference in the internal sound card vs the USB DAC here, not so much the AMP) I think that if you are set on these headphones, that you should start out by getting them, and listening to them from a friends iPod. I use my iPod Touch with IEMs when I moving about traveling, and then the ESW10JPN for laptop use at the beach and in a hotel. The ESW10JPN is definitely sensitive enough to run without an amp. You might find that you like the sound right out of the iPod, and save the $$$ and weight and hassle of an external amp and LOD.
Not that the amps don't make a difference. I get better bass and treble extension with an amp with my IEMs and the ESW10JPN. If I am actively moving about though, I usually don't worry with an amp. Its great watching a movie on the iPod Touch via the Shadow and nice IEMs on a plane ride.