When i watch movies on my tiny HD player, i just plug the HD 598's straight into the LED TV jack. No amps, no anything in between, and it sounds fantastic, with excellent bass.
A while ago i watched movies like Hangover II or Crazy, Stupid, Love. What these two movies have in common is that the main characters are going to bars or clubs. The atmosphere, the bass, that is strong and heavy on the background, and even the room size are well reproduced on the HD 598's. Very realistic, feels like you're there in a large room filled with sound from everywhere.
If you liked watching movies on the HD 518 and HD 558 models i don't see any reason you won't on HD 598.