Hi, I ended up getting the HiFimeDIY Sabre DAC with Brainwavz HM5. I'm very impressed.

http://hifimediy.com/index.php?route=product/product&product_id=87 I think I'll go for this slightly more expensive version because it supposedly has better performance, it looks a lot more durable, and I would love having the volume dial. Also, for indie rock music, do you think the Sennheiser...

Looks good. How powerful is the amplifier? (General impedance. I know sensitivity matters too.)

It's out of my budget sadly.

It must be usable through USB. Preferably not too big so I can switch it between my laptops. It must drive AKG K550s well, and preferably have some upgradeability in it. Currently I am considering the: 1. SMSL Fort -...

The DAC/amplifier that I plan on getting has two outputs if that'd work?

I'd like to have music and stuff through some open headphones, for the better sound and so called airy feel, but I also don't want my parents to hear all the swearing and stuff on Team speak whenever she comes near my room. I was wondering if I could have all audio play through the open...

I think I'll go for the K550s over the DT770s and K551s, because they supposedly have a better wire and are more durable. Also I don't need the remote control and mic.

How durable are the DT770s and K551?

I will be using these with a Dacmagic XS. Which would be better? I listen to all types of music, from Disclosure to Wilco to Sixpence None The Richer.

Do Philips Fidelio L2 need an amplifier?

Well I guess I'm better off with the EHP-O2D as it is cheaper. Thanks!

How does this compare to the Schiit stack (Magni and Modi)? Here in the UK, I can get the Schiit Magni and Modi for £200. I can get the EHP-O2D for £187.

So far I'm leaning to the HE-300s. As this is my first venture into good headphones, I think that would be more suitable than diving straight into neutral cans.

Oops, I meant balanced/neutral or warm. Edited the post to reflect that. Thanks for the suggestions! It gives me a good starting point to find out more about each of them!