This is an interesting thread with some strong opinions. I think the best suggestion is to get a couple of different headphones and try them out. My conclusion is that until they are on your head playing your music through your system it's all speculation.
Here's my story. I am listening to a brand spanking new out of the box pair of Grado 325is that arrived 2 hours ago. So no breaking, no getting used to them, or any of that. I chose them because the Grado fans are passionate, really passionate, about them. The Grado haters hate them with huge hate. There is just no "Meh" about them. I was feeling kinda meh about my listening, so I thought I'd try them. I've got some history with the 60i so it's not a complete flyer.
Looking at my set up I see Sennheiser 800s (saw my ears off with diamond clarity), Audeze LCD-2 (2nd Ed) which I listened to for a year straight, thrilled with everything I heard - until about a month ago, then I started yawning. I have a very old pair of AKG 701 - snore. I take them out of the closet about twice a year and usually put them back the same day.
But as I listen to the 325s I think they are brilliant: Rattle's Bruckner 9th (my current favorite) was engaging, Schiff's Bach Well Tempered Klavier was great, and the new weirdy of the week, Recomposed by Max Richter, is doing surprisingly well. My very limited time says these Grados are just fine for classical music, and today I would recommend them.
But, and here is the point I'm making: that recommendation is today only and for me. The current state of my ears, the fact that I'm listening to very low volumes, a tinnitus flare up, etc. all factor into what I'm hearing. Take our recommendations as a rough guide, but let your ears be your guide. Let what you are listening for (are you listening for fun, as a recording engineer, discovering different styles, trying to make your library new all over, . . . ). All that factors in and puts simplistic, black and white statements in the trash. Grados are horrible for classical (that opinion is all over head-fi). Grados are great for classical (search and you'll find it - today I'd join). One might say that both cant be right, but they are once you factor everything else in from source (I'm mostly apple lossless and iTunes download), equipment (Schiit Bifrost and Lyr or my iPhone 4s) and the state of my ears.
So go buy what intrigues, buy from someplace that will let you return, and enjoy what you have at the moment. I'd hate to have you not enjoy the Senns because you think the Grados might be 4% better. I've been fortunate that I could indulge in multiple headphone and change the nature of my system with the switch of a plug (try that with floor standing speakers!), but the purpose is to get sounds to your ears so the music can move you. Anything recommended here will do that.
I don't know if this makes sense, but I hope you get the phones your gut tells you and that for however long you can you enjoy the music.