Did you look at what is available at HeadRoom? They review all of the cans right there online. It is a good place to start in any case, they give you a little review and a frequency response chart.

HeadRoom
http://www.headphone.com/

You might look at Sennheiser HD280 pro. Within your price range, closed -very good seal, very durable, comfortable, 64 ohm - no problem driving them without a headphone amp. Reproduction not the equivalent of 580's, 600's,650's, but more than adequate. Can't think of anything better suited to your needs.

Good Luck,

Another contender would be the Sony V6 or 7506. Good seal, decent sound for about $70. If you need more portability, the Sennheiser HD 25-1 is pretty good for about $150-$200. Don't confuse these with the HD 25SP, which are not up to par.

i realize these aren't "seal-type" headphones, but grado's iphones for around $50 are stupid good and for college or dorm use can take abuse and if they are destroyed, get another pair! you are still under your $250 tops price range.

I was looking around for some nice head phones for my son and found a nice pair at Sound on USA

he has found it a great advantage to have a wireless pair at school.

Don't know if this fits your criteria but the YuinPK2 is an earbud that rivals some 200.00 headphones. I got it for my son's Ipod and was astonished at how good it sounded.
So I bought the YuinPK1's for myself , but they are best with a portable amp.

PK2 is 69.00
PK1 139.00

Both are so much better than anything else i"ve heard in that price range that it really is surprising

Forget the sealed cans. While your'e trancing on X your roomies will be stealing your beer and weed. Go with the Grados. The 225's will keep you under budget and are highly recommended by the same people who buy $3000 speaker cables.