[Glow Fish]

Also, re isolation -- D2000 has poor isolation, surprisingly poor.  K550 is decent but not the best.  I have a pair of HD 25's that isolate very well and are highly detailed.  Those might work for your preferences.  But I don't find them very comfortable for long durations and the soundstage is nothing to write home about.  K550 has the best soundstage I have encountered in a closed headphone.
 
Now that I think about it, the D2000 are probably not a great choice for no amp.  Both the K550 and HD 25 can benefit from amping, but are great without it.  For a closed Beyer, you may want to consider the DT 770.  That is truly closed, unlike the DT 880 (semi) and DT 990 (open).  DT 770 isolates well, but the Head Fi community seems to have a love/hate relationship with the sound signature.  I just got a pair that are not burnt in yet.  Out of the box, the treble was harsh.  Hopefully that will improve.

 

[Dyaems]

agreed on both points regarding isolation, specially the d2000. they are like open headphones due to poor isolation similar to CAL/d1001. and it is heavyyyyyyyy... not that heavy but heavy. if you have long hair and you shake your head, the d2000 will fall off.
 
send me another pair when you get it working for the t50rp! =)
my t50rp has somewhat lacking in treble but i dont want to lose the bass impact (which i love) i am getting if i try to increase the treble
 
im no basshead!

 

[valerianaoff]

Denon D1100 seems to have great reviews...maybe can try them out? I am thinking of purchasing them...
 
Pretty good really...
 
Just an option for you to consider...

 

[dweaver]

I love the SRH-940 but they don't seem to be built to last so will go with AKG-550 or Sony Z1000 which can be found for the $300 mark new if you shop around on the net.

 

[FABZ]

For those who care, I have bought AKG K550 a week ago for $299 (original price $350) on Amazon.
 
I'm highly satisfied with my purchase. It is extremely comfortable with a good enough isolation, and most importantly an excellent sound quality.
 
Thanks to everyone who contributed to this thread. You've all been a great help.

 

[CantScareMe]

Good choice.
 
Best of all, you're happy