128kbps is noticeably worse sounding, even on a much cheaper headphone. In a nutshell, it'll sound better than it would have sounded, but at the end of the day it is still 128kbps. You don't need to go full-on lossless, but if you can convert your library to V0 MP3s, it'll sound significantly better.
As for my suggestions, I'd suggest looking at the KRK KNS 8400, Brainwavz HM5, or SRH840. I've linked to some reviews for each of them.
Quote:
Originally Posted by
TemurAmir 
Hi all,
I'm looking for good all-around closed headphones recommendations for 150 max, unamped. I listen to classical, techno, and some hip hop from my ipod or computer. I'm mostly concerned with build quality and sound isolation and will be using them on the go so portability is another factor. Since most of my music is ripped at 128 bit rate, would I have to rip them again lossless or would the 128 bit rate sound okay with higher quality headphones?
Thanks in advance