I went with dt770s over m50s and personally, I wouldn't mess around with wireless stuff.
I bet those Sonys would do the trick, however I just wanted to make sure you noticed that they have a 10-ft cord. Of course you can wrap it up, but I've had headphones with long cords in the past and they were always more difficult.
If you're studying in a library or with others around you, make sure you get a pair with closed back. The two you chose do have closed backs so maybe I'm preaching to the choir. Closed backs will prevent your sound from leaking and bothering those around you, and it will also improve the sound isolation if you're studying in a noisy area.
Personally, I have the 32-Ohm version of the Beyerdynamic DT-770s and I can highly recommend them. If they're definitely out of your price range, take a look over at Head-Fi for reviews and the forums also have lots of great information. There are lots of great options in the ~$100 range.
general consensus
heh. :D
Do you have a music store nearby with some patient staff? I listened to a reference track for 90 minutes on 15 different headphones before settling on some closed-back low-ohm Beyerdynamic that felt sooo nice with the velvet finish. Then I went and bought Blue Mo-Fi:s anyway (unheard!!!). Slightly uncomfortable, but the best on-ear/mobile sound I've ever heard.