I think some folks mistake the HD800 for an entry level headphone that can be plugged into any chain with impunity. If you're squeezing every penny just to fit the HD800 into your budget, be prepared to accept the possibility that you'll scratch your head at all the accolades. You don't need to spend megabucks to make the HD800 sing, but there are many here who have gone through many combinations of gear to get to that point. Some skip the hassle and aim for the very top, but it's likely both groups have invested just as heavily when it's all tallied up.
More power to those who are deeply content with the HD800 from sound cards and other budget components. The HD800 epitomises Head-Fi, imo. It gives you a glimpse, a lure for your wallet and sanity. Unlike the usual Head-Fi hyperbole though, the payoff from the HD800 - when you get there - is real and immensely rewarding.
edit: The HD800's bass is my favourite aspect of its signature. The extension and clarity, the way it occupies its own space - fading when its meant to and slamming hard when called for - is what gives it "body" imo. It is distinctly defined. People that rue the lack of body they perceive are likely describing a preference for emphasised low end, one that is overbearing and smears the overall presentation, less refined but perhaps more "fun" and "musical" to their ears. To each their own. I'll take the realism from the H800 every time.