mlchiangit really depends on what you're looking for in a pair of headphones, plus, they are actually quite different, in price, open/closed back, etc...
micahpbtI'm pretty new to the audiophile community. (just lurking) so this will be my first real pair of headphones. So I guess I'm looking for a good starting pair.
mlchiangHands down the k7xx if you're using them in a quiet place or at home, if you plan to go outside or noisy places then the m50x since they are closed back.
mlchiangI heard the m50x is a good pair...but the Philips Fidelio L1 is on Massdrop right now, and they sound pretty good too for around 110USD. If your budget is 200 dollars u might have more options like the MDR1R, V-Moda XS on Amazon for 200, or you might be able to e-bay a pair of B&W P5 Series 2 for 200 as well. There is always Sennheiser Momentum Over Ears, and Focal Spirits. These however, are just suggestions. Hopefully you find the right pair for your listening pleasure. If it turns into an obsession, then welcome to the club. Happy hunting :)