I apologize if this is in the wrong forum, but my topic seems to span headphones, amps, and DACs. Likewise, I do not know of any don't-start-your-own-thread-ask-for-suggestions-here thread for amps or DACs. Suffice to say, I flipped a three-sided coin, and it landed on "Portable Source Gear". Thus, here I am.
I recently purchased two new (used) headphones (the ATH-M50 and SR80), and I intend to eventually own another (the K550). But what now? I know that all of these work fine without an amp, but would the purchase be worthwhile? Likewise, would I notice the addition of a DAC?
I listen directly out of iTunes on my MacBook Pro while at home, or out of my iPhone 4 on the bus. Thus, something fully portable (i.e. I-can-strap-it-to-my-iPhone) might be preferred, but I also obviously want to be able to use it with my laptop. Or I could be completely wrong and should just buy something for desktop use, in which case you should tell me.
Let's say my budget is under $200. With heavy emphasis on "under".
Thanks much for the help.