Thanks, everyone. I can get a pretty good discount from this one retailer because I have family that work there. I would not rule out used cans, provided I can easily and affordably replace the earpads (used earpads gross me out).
But based on these posts, I will focus on the best Sennheiser's I can afford (factoring in my discount) as well as the Sony MDR-7506. The retailer offers these at $100, and I expect a substantial discount, although with Sony, you never know. (Many years ago, when I worked in retail, Sony was notorious for not allowing retailers to make any profit on Sony products. Sony's attitude was that Sony products bring so much traffic into a retailer that there is no reason to allow them to make a profit off of selling their products. Perhaps that has changed.)
I have a birthday coming up, and this will be my gift to myself.
I totally agree with the posts that point out that Grados, while beautiful sounding cans, are not the best choice for monitoring. Horses for courses.