Grados would be great. For metal though I really like Ultrasone too. I kind of overlooked them when I got into audio, but I tried them a year or two ago and fell in love. They're almost as aggressive as Grados, depending on the model, and they're just fantastic for bass. They're just 'fast.' This is the one thing that always surprises me when I compare the SR225 to my HFI-780s. The Ultrasones are just brilliant at handling faster repetitive drum kicks. The mids are better on the Grados, though.
HFI-580 or HFI-780 would be great, and you'd have enough left for a DAC or something. If you went for Grados, I'd have to recommend the SR225 over the 325's, personally. The 325's were kind of fatiguing for me. I also thought all of these were noticeably better than M50s or HD25s.