HD25-1 II - not the SP.
I agree with the suggestion. Also, M50s are good for portable use, although a little bigger than the senns.. Not sure if these headphones sound anything alike the AKG. AKG K518 is a little bassier supra-aural one and AKG K450 is a pretty small headphone. My wife adores it, although I don't have too many good words about it.. YMMV of course.
Edited by Coq de Combat - 1/3/12 at 5:15am