I NEED HEADPHONES....NOW

If you search around you might be able to get a pair of Grado RS 2 for $300. I did and I feel these are excellent cans. I never tire of listening to them.

I own both, Grado RS-1 and Senheissers HD600. Let me tell you that even the grados are twice the price of the HD600 I prefer the HD600 over the grados in all music genres. The HD600 are more neutral with a bigger sound stage and a bass as deep as the bass in the grados, but the bass in the HD600 is better because is faster and better controled than with the grados. I don't know why some people say tha the grados have better bass than the HD600, I find the bass in the grados slightly (just a bit) boomy in comparision with the HD600. I also find the sound in the grados a little coloured that is nice for some people, not for me. Anyway this is my point of view on these two cans. I also have the Musical Fidelity XCANv2 headphone amp, which I consider very good for the price. Good luck in your decision. Jorge.

I have a pair of Sennheiser HD 580's and a Pair of Denon AH-D750's. The Sennheiser's are great at low to mid listening levels, but the Denons handle alot more power and subsequently deliver more SPL. I listen to the Sennheisers when I'm in a relaxing mood listening to smooth jazz. But if I've had a few beers, and want to pump up the music L-O-U-D, then the Denon's are my choice.

Firstly, I suggest going to headwize.com and you will find an entire website dedicated to headphones. Use their search engine (if it is working) to save time.
If you re-read most of the recommendations for Sennheisers you will find that most who like them use a dedicated headphone amp, frequently with tubes. The only way I have liked the Sennheiser 580 or 600 is with an Earmax. This combination sounded terrific, but is much more than $300.
I prefer Grado's but I do not wish to bother with a dedicated headphone amp. I have Grado SR-80's and RS-2's and like them both. I just picked up a pair of Denon AHD 750's to try for summer listening (when the air conditioner is on) and they seem to sound good for a sealed can.

I forgot to mention that you need to consider not only sonics but comfort when shopping. I use the SR60 earpads on both of my Grado's and I rest my eyeglasses on the earpieces of the headphones. Some other headphones do not work well with eyeglasses, some make your ears perspire, etc. If the phones fit tight initially, imagine how they will feel after an hour or three.