I'm looking to buy a headphone monitor for electric guitar tracking and mixing. My budget is $150-200 USD. I don't have much knowledge or experience with headphones so I checked up on Head-Fi.org and the ATH-M50 and Sennheiser HD 280 seems to be heavily recommended. I am currently using a Sennheiser HD 202, and the bass is way too overpowering.

Going through various ATH-M50 vs. HD 280 threads, its been said that HD 280 is better for tracking due to more isolation, while ATH-M50 is flatter and better for mixing. Right now I'm leaning towards the ATH-M50. The thought of buying both has crossed my mind, but I'd REALLY like to avoid that.

Which one would best serve for my purposes? Any other suggestions for headphone monitors are appreciated.

Get the ATH-M50. "Better for Tracking" is bullcrap. Why would you need to isolate sound in a recording environment? If There's too much you should record somewhere else.