Quote: Those that are designed for portable use often don't need an amp to "start to sound good", it also depends on your source (what you plug it in, ie ipods, cellphones...). But some of them probably benefit from amping (that is to say, a good amp may help to get the best out of them - there won't always be day-and-night differences though). If you travel a lot, I'd suggest to just skip the amp. From your music preference, I'd just pick the Ultrasone HFI-580 (it should have the type of bass you want and more) or Ultrasone HFI-780 for better overall clarity. They isolate pretty well and are well-built IMO. Spending more doesn't always mean you will get better SQ. But I guess it's your choice. When it goes past a certain price point, the difference is more marginal, it then comes down to a matter of taste. GL with the purchase.