Well to be honest.. I don't want to answer you these questions because I don't consider myself capable of investigating the sound qualities. I am not confident enough in my "ear'' skills to tell you whether the lows/mids/highs are good/perfect/incomplete etc.
However I can help with this:
When I was looking for over-ear headphones my price range was ~100$ (plus/minus 20$). I listen rock/metal music mainly and I was in deep consideration which one from these 3 to choose:
1) Sony MDR-ZX700 --> http://www.youtube.com/watch?v=xgJ3jIVU1f8 By far the best review I have found
2) Audio-Technica ATH-M50 --> It is said a lot for them in this forum (but 2,5m cord length is probably a stop-sign for you)
3) Creative Aurvana Live! ( CALs) www.amazon.com/Creative-EF0060-Aurvana-Live-Headphones/dp/B000ZJZ7OA/ref=sr_1_3?s=electronics&ie=UTF8&qid=1325643505&sr=1-3
Fair to say, I ended up with Sony because I found them for 75$. + I knew their isolation is superior to the others.
Look up the videos in youtube made by "InnerFidelity" no doubt they'll be really helpful for you.
(I find them with GREAT balance if you're interested.. but for David Guettta kind of music I am sure you can find headphones with more interesting sounding) Sony MDR-ZX700 is said to be perfect for jazz music (as it is perfectly balanced, they say) but you can EQ them fairly well too.