This thread is inspired by another: view original post
The HD205's are more portable than the 558's. If they're anything like their predecessors, neither of them need to be amped, so it'll be fine to plug straight into your iPod. I have a pair of HD555's that I use on my desktop. I've de-foamed them and they sound great, but Sennheiser's build quality leaves a lot to be desired. I'm looking to replace them some time. I'm currently looking at AKG models for a replacement.