Heyo LegendOfLich
Cool to see you upgrading your headphone game a lil'. As for the M50X's I'd stay away from those. They're way too over hyped Imo. I own both the M40X's and the M50X's and the M40X's litteraly destroys the M50X's for the price. There is little difference between them, however the M40X's doesn't have those super annoying treble murder highs. The m40X's will however need som replacement pads. The stock aren't that great. Place some Brainwavez HM5 pleather pads on them. This will increase the soundstage and a little more bass.
Now when that's said. I have some other suggestions for you to consider.
Persoanlyl my first pair of actual headphones was the Beyerdynamic DT770's. A great pair of closed-back headphones with insane low-end. The produce sub-bass like I've never heard before. This might sound like it's overwhelming, but don't fear (lol), they're somewhat -balanced- throughout the spectrum. They do have elevated bass and treble, however still miles ahead of any beats, bose, skullcandy or any other bass-head headphone.
Some Sennheiser HD599's are also a solid choice. These are an open-back design. If you didn't already know, this means you can hear things around you, but things around can also hear what you're listening to. I'm a Sennheiser nut myself and actually enjoyed these the few days I owned them. (Sold them off to a friend who needed them more than I did).
When it's an open-back design you'll get a more natural soundstage and sound in general. It will sound way more open. This might be weird the first time around, but trust me. You'll love open-backs when you've first tried a pair.
There's also the closed-back "edition" of the HD599's. The Sennheiser HD569. They sound very familiar, however the "natural sounding soundstage" will disappear a little.
If you're a little more cheap, there's the Takstar Pro 82's. I personally use them for transit atm. They're quite good for the price and have alright sound quality. They "try" to be the M40X's. However either they have a little too much low-end or have a little too much treble. They have bass ports on either side of the cups and you're able to control the low-end there.
Cheers