Hell, they're cheaper than the crap called Beats.
How can Beats be crap? They're designed by a doctor, and (until recently) made by a Monster!
I have a pair of older closed, full-ear Sennheiser headphones that are my "best" pair; I got them for under $70, IIRC they were the model under the 555 when they sold those. I didn't know about Grado at the time, that may have been a better choice. I also have a pair of wireless Sennheisers for TV viewing (by far the best wireless headphones I've used, RS120 I think) and an ancient pair of Radio Shack (rebranded Koss) on-ear headphones (from the '80s). They all sound different, and they all sound good to me.
Note that only the RS120s are current models, and I've even had those for ~10 years. Good headphones will last forever. Try to buy from a brand that sells replacement ear pads.
Try to get them from somewhere where you can either listen to them with your music or return them easily. Headphone preference is fairly personal, so you might hate the ones I love.
If you're really serious, you'll also want to build a small headphone amp. You could buy one, but then you'll have to turn in your soldering iron.