A lot of people prefer the m40x to the m50x. I don't have either, so I can't test them against each other, but that is just what I have heard from other people. 

If you want closed, I would actually recommend the m40x over the m50x, and then you should replace the stock pads with either zmf or hm5 pads.

I don't have experience with either, but I think the audioengine D1 will be better, but it is also $70 more expensive. 

If you want to get the fulla 2, the cheapest you will be able to find it for is at schiit.eu.com.

The 598 is good, and since it's impedance is only 50 ohms, I would say that you don't even need an amp/dac for it. 

Open headphones generally have a more natural sound, but because they are open there is a lot of sound leakage in and out of them, so it depends on what environment you will be using them in. If you are going to be using them in a quiet space I would suggest open, but if you think you may want...

I think I may be able to come, when about will the meet end?

Try looking at the Sennheiser Momentum 2.0 for apple, I think they should fit all your requirements, and will sound better than your bose on ears.  

western mass

I'd like to come, but I'm not sure if I'll be able to figure out transportation in time. I'm just getting into this hobby, and thought it might be interesting to try out some other equipment. 

The r70x is usually at around that price I think. Most headphones are always sold for less than what the msrp is. The r70x might be a pair to look at, but I think a lot of people prefer the a AD series from audio technica to the R series.

Gaming headsets, razer's included, tend to have not very good sound quality. I would suggest looking at more established audio companies like sennheiser, AKG, Hifiman, etc. when you have a few headphones in mind, check the store locators on the companies websites. There were a few small somewhat...

Nice, I would suggest going to the closest audio store to where you are, and trying out the headphones you are considering, then you can make sure that it is a sound you like before buying.

you could get the schiit fulla for $60, or the SMSL SD793 for around $60-65. Those are headphone dac/amps, which would probably give you better sound quality than a sound card. Though, if you get the SMSL one, check your motherboard before buying, because it only has optical and coaxial digital...

An e17k would be enough to drive the HD600s, from what I've heard, you could also get away with using a fiio q1 with them. Would you be using your phone or a computer as the audio source? Because there are other, probably better sounding solutions that would work if you are thinking of using it...

An amp/dac or sound card will allow you to make them louder, and will likely get rid of the static, but I'm not sure if it will help at all with the base. What headphones did you have before you got these? It could be that they had a more base emphasized sound signature rather than a more...

What is it about the sound that you don't like? A sound card or an amp/dac may be able to help depending on what it is that you don't like, or it could just be that you don't like the sound signature of the headphones that much.

for 32 ohm headphones, you won't need a sound card. 

New headphones will generally give you the largest improvement in sound quality, but specific values cannot be assigned to how much improvement you will get for each upgrade, because it is different in every scenario. I've tried my HD598s with an amp, and there wasn't that much of an improvement...

Your onboard audio may be able to make 600 ohm headphones load enough, but they won't sound nearly as good as they will if you use an external dac and amp. However, with the headphones you are using the on board audio will work fine, so save your money for a nicer pair of headphones instead of...

The status cb-1s are great if you want closed back, and if you want open back I would recommend the philips SHP9500s. You won't need to worry about an amp for any of these headphones. Generally, you don't need an amp unless your headphone's impedance is more than 50 ohms. There are some other...

The dragonfly is good if you are using it with a computer, but I wouldn't recommend it for a smartphone. Because it doesn't have a battery, it pulls all of its power from the device it is plugged into, and most smartphones aren't designed to give that much power. If you are sure you want to get...

The e11k would also work, however it is only an amp, not a dac/amp. The HD600 and HD650 aren't the best built pair of headphones, but as long as you aren't tossing them across the room, you'll be fine. The same can be said for the he-400s. 

I like the Sennheiser HD600s alot (and there isn't any leather on them), they are some of the most neutral headphones you can find, but if you prefer a bit of a warmer (more base) sound, the hd650s are also good. For a portable amp to go with them, the E17k would work, though a less expensive...

Try setting your phone and other devices you might have near your computer to airplane more, when I tried my headphones with a friend's portable amp, it caused static in the right channel when my phone wasn't on airplane mode. If that doesn't work I would suggest contacting Schiit support.