My point is that $300 headphones won’t necessarily sound better than $100 headphones, if you have a crappy soundcard. Instead of spending all that money just on headphones, you will get more out of it, if you buy a soundcard for $100 and headphones for $150.
EDIT: Or just buy $100 headphones, that’s also fine. Just be aware that other components also affect the sound quality and don’t overspend on headphones that you can’t fully appreciate.