Hi, I've not tried the ipod classic, but I can pretty confidently say that it will drive the 598s to an ok volume as they are made with mobile devices in mind. However, you will most likely not get massive volume from those devices. I never can from any of my android phones. It's loud enough, but you may want more. In that case, they bnefit from amping and anything will really help them to get sufficient volume as they are not that hard to drive, but if you plan on getting bette/harder to drive cans in the future, then my recommendation is easily going to be the Cayin C5, which drives ANY headphone brilliantly and is portable. Of the genres you mentioned, the 598s do great with Jazz, Classical (they sound AMAZING with small group stuff with their amazing soundstage). But, for metal, they do show all the details up and present everything to you, but they are a little slow and polite sounding, so metal can sound a little tame and lacking aggression. It's not terrible, but there are better options for metal. Still, I would be happy if these were my only cans for all genres and would accept that compromise with the metal for everything else it does so well. For a solution for your PC, I would recommend without doubt the HRT Microstreamer, which is an amazing DAC as well as an amp, so with the 598s, you'l hear a BIG step up in performance. Also, you can use the HRT on your smartphone as well, so you can take amazing sound out and about with you. Good luck!