portable headphones ~$250

[Niurez]

Hey all,

I am a newbie when it comes to your knowledge about all different kinds of headphones and I am pretty underwhelmed by all the different choices.
The headphones I stumbled upon and which looked great for my needs were the AKG K550. But I do not know if they truly are what I am searching for.
So perhaps it is best if I give all my requirements.
I am looking for headphones that are in a pricerange till $250.
Also since I will be using them quite a lot when I am on the bus or in other loud environments I require them to be closed (dont know if this is the appropriate word), I wouldnt like to hear too much noise from other people nor make a lot of noise myself.
I mostly listen to rock and blues (big fan of the rolling stones) but I also like modern pop music. I mostly use them on portable devices or on my computer.

After some more research I also found some good reviews about the DT770. But there are different versions like the pro and the M version but also difference in ohmage. What would be the most appropriate to use with the iPod (dont have a cowon, yet )? Is the DT770 better for rock and some dance music?
Should I save some money to buy a decent amplifier?

Songs I listened to recently:

-Florence and the machine (unplugged) - Only if for a night
-The rolling stones - The last time
-The wombats - Jump into the fog
-Rihanna - Who's that chick
-Kasabian - Days are forgotten
-Fever ray - When I grow up)
As you can see if I have a pretty broad taste of music!

The headphones in the running are: AKG K550, DT770, ATH M50, denon ADH2000 and maybe sennheiser hd598

I like the design of the AKG K550 best.

What do you guys think?