uhh, Sony MDRs are NOT good headphones. One could argue that for the money they aren't bad, and while they aren't THAT bad for low end, sealed headphones you could do a lot better if you looked around.But he wants to spend aroun 趚, so lets forget about them. If you want open headphones, I'd go with the Senheiser 600s. You might have to go a bit above your budget, but these are widely regarded as the best in the industry. You can also get the HD580s for around โ less. Grado is also a reccomended manufacturer, I've heard good things about the Grado SR225s.
Now, if you want a good pair of sealed headphones, your choices are slightly tighter. Beyerdynamic has a line of good sealed headphones. The Beyerdynamic DT831s are supposedly the best sealed headphones you can buy, you can get them for around 赀. You could also consider going the earphone route, if you want. The advantages of this is that they're easy to carry around, and provide GREAT isolation between your music and the outside world. The Etymotic ER4Ss are the best, and around your price range. They sound great, in fact some say better then the Senheiser 600s.
I've hit upon the important brands here, I think. Do yourself a favor and go to Headroom (http://www.headphone.com/) and look around, I promise you'll find great comparisons and guides. You could also try the a/v forum at www.arstechnica.com, do a search and you'll find some great opinions.
Also, be sure to factor in a couple hundred for a headphone amp, if you don't have one already. It IS needed if you want to get decent quality out of your new headphones.
