Denon 2000/5000? Got my D5000s on sale for $399.00
you could see if you could do the 'lite' version of the magnum upgrade on your grados. It's usually the 325's that get moded but it's not required and the drivers get replaced anyway. These are FANTASTIC phones.
Dt 880s... getting mine in 12 hours
They say the Mids are ever so slighty recessed on the Dt 880, but I guess it depends on the kind of rock music your talking about, I plan to play this on my Dt 880s and I'm confident it will sound great :3 [in 12 hours ill know for sure]
So rock can of course be as unique as that with a mix of many wonderful elements, or it can be simpler and maybe needs less attention... still :3 in 12 hours we shall know! [or at least I will]
I can vouch for the HD 600, but since it's the only headphone I own in that price range I can't give much comparision.
I think my HD 600 sounds absolutely amazing and I would strongly recommend it. Mighty comfy too.
I've decided to mod my SR80i & turn it in to Magnum one.
Already got the woodies, headband G-Cushions & just waiting for the V5's to arrive.
I'd like to thanks everyone who recommended a set of cans here - I'll probably use these recommendations for my next cans.