Hydrith

Agreed. And depending on what kind you buy, there are different recommendations: Over Ear: Audio Technica ATH-M40x In Ear: MEE audio M6 Pro The reason why I recommend these two sets are for the same reason: their tuned in a neutral fashion instead of being bass heavy (like the Sennheiser Momentums or the ATH-M50x), which means you're hearing the music the way it was recorded, not with the low tones expanded upon while the rest of the audio suffers. The ATH-M40x is, IMHO, the best over-ear headset you can buy for below 100 dollars, and don't need any kind of AMP to boost their capabilities (they're around 35 ohm resistance). And, if you like buying other sets of ear cups for your headphones, anything that works for the ATH-M50x will work on the ATH-M40x. On the other hand, the Pro 6 earbuds are fairly consistent in their review as being excellently tuned earbuds that come with a lot of extras in the $50 purchase. Multiple sets of cords to interchange (one w/ a mic (for use with your cell phone), one without), carrying case, multple sets of earpieces (including a set of Comply foam buds (which are awesome)). It's a nice package. Also, I know several people who have bought them who stopped using more expensive earbuds because they thought that these sounded better.

... I think you left your /sarc tag at home. Let me provide you with one. That being said, not all sound cards are created equally. My Soundblaster Zx sounds a lot nicer than the Asus Xonar that I owned (and returned).

Agreed. That being said, the best noise cancelling Mics I've had were attached to a headset when they shipped out of the factory. Nothing against Modmics, but they don't seem to have the ability to cancel out noise as effectively as headsets w/ "noise cancelling" mics built into them. Of the headsets I've own that claim that, I'd say that my PC360 G4ME headset does a better job than my Nash 20 does, though considering the fact is was twice as much may be the reason

Depending on your interest, I would recommend the following: USB (Dolby 7.1) Plantronics RIG Plantronics Gamecom 780 Logitech G430 3.5mm Sennheiser GAME ONE Mionix NASH 20 Razer Blackshark Having owned most of those at one point or another (currently using the Nash 20 for Closed Aural and the PC360 G4ME (the 1st gen model of the GAME ONE) for Open Aural), I would say any of them is a good purchase.

I agree with this. Most modern Sound Blaster cards/components have a Headphone Amp built into them. I'm especially fond of the Soundblaster Zx and the Omni 5.1, both of which have built-in amps and aren't terribly expensive.

Ultimately, this question is extremely difficult to answer without more information. Obviously, if price is no object, you can buy a high end set of cans that can do a lot of things, or buy several pairs for the specific needs. Bass heads will not enjoy neutral sounding headsets like the AKG K240 MK II or the Audio Technica ATH-M40x sets. On the other hand, naturalists will find the Sennheiser DJ series and Audio Technica ATH-M50x sets unacceptable. Good middle grounds are few and far between, especially in the lower price brackets (in my experience, you have to spend a lot more money for those kinds of cans). I'm more of the latter buyer, having multiple sets of headsets for different purposes (I own about 6 different sets of headsets/earbuds for different purposes) AMP/DAC wise, unless the OP is planning to throw a set of 600 ohm cans at their device, a decent aftermarket soundcard/amp is probably more than enough to meet his needs, IMHO.

Between the two of them, I would recommend the HD558, mostly because I own a set of them and love them (along w/ the PC360 G4ME which is just a HD558 with a Mic built into it). Nothing against Audio Technica (I have a set of ATH-M40X, which are nice under certain cirumstances), but build quality is a night and day difference between AT and Sennheiser (IMHO).