Hi everyone, many greetings from Croatia!

My first post here :) and It has to do with both PC audio and headphones. I am posting here because I think headphones are secondary to my questione(s).

I have "some" knowledge about hi fi so am not a total rookie but for years I was out of the game and need a quick update. I would like to put together a PC/headphones solution to enjoy music both at home and at work.

- Output device: I have my heart set on either used Sennheiser 580 headphones or new Grados 60/125. Pricewise - this would be similar. Any tips here?

- Source of music: my Macbook Air, 1.7 Ghz processing power and 4GB RAM. I would feed FLAC files or highest quality WMA.

- Type of music: mostly classical (actually baroque but lets leave correctness out of it ;)), but also blues, rock and heavy metal.

What else will I need? As I have read on this site, it seems that usb D/A converters are what I am looking for? Music plays on the computer, D/A converts it to analogue signal, then I'm guessing I need headphone amplifier and finally headphones, right?

My budget is quite limited, so, for the suggested listening type, what D/A converter should I shop around (if any) and what headphone amplifier?

Thank you so much and sorry for the ramble, English is not my mothertongue! Cheers all,
Alex