I believe that Grados will spill sound out into the workplace. If that is an issue, I recommend Sennheiser HD-280 Pro. Closed-back, as opposed to Senn. 580/600/650 and Grados, and with amazing isolation both ways— no one else hears your music, you don't hear anything else. Sound great, under $100 new, and you don't need a headphone amp to drive them. I use them on my commuter train with a portable CD player; have pricier cans and dedicated headphone amp at home.
Also, much more info available at head-fi.com. Good luck.
Also, much more info available at head-fi.com. Good luck.