just to provide a little contrasting opinion here, I have grado rs-2 headphones, which I love. (let me preface by saying, I'm not great at describing in words what I hear). before I bought the grado's, I did do a head-to-head with Senn HD-600. to me, the RS-2's made the music jump out and become more real and lively. (and they certainly don't lack anything in the low end. in fact, the bass extension is wonderful).
I don't mind at all the way they sit on my ears, so the purchase was a no brainer. in the end, they are both great headphones. you should listen to them head-to-head and see which you prefer. It's definitely a good idea, and it'll ease your mind to know that you bought the headphones that you liked best.
side note - gloco - out of curiousity, which headphones do you now have, that took nearly a year to track down ??