Thanks for the info fellas, I decided to go for the DT880 from Beyerdynamic in the 250 ohm version, my dealer said it would be great for portable use (just with iPhone for now) and to leave a little headroom for an amp in the future.   I was looking at the Heed CanAmp, very warm sounding and...

I have had my eye on a pair of Beyer's for some time now, just noticed they have gone on sale for 30% off from my dealer. Would anyone have any recommendations between the 770/880/990?  I am looking to get a 250 ohm version as I do see a headphone amp down the road but, I will also be using...