MaloS, I know you've owned and/or had the opportunity to hear many different headphones in multiple rigs from budget to stratospheric in cost, more rigs than 90% of the members on this board if I were guessing. You're aware of how unrealistic the requests are by some members, but that's because you've both the experience to know how unrealistic it is to expect everything for nothing, and also because your tastes and listening skills have been refined over the years. I strongly suspect that unless someone already has a pretty good grounding in high-end audio, he or she might think it's perfectly reasonable to expect near-perfection for $100, $200 or $300. After all, these are just headphones, aren't they? Also, what someone's standard is for "deep tight bass, natural sound with warm midrange, clear sparkling extended highs, lots of detail, great soundstage for X amount" might be very different than yours, as I'm sure your standards have changed as you've been exposed to higher quality gear. I know mine have, and it's really hard to go back or even remember what once used to blow me away having since heard better. I guess what I'm trying to say is that what might be the definition of "tight bass and lush mids" to someone coming from ipod earbuds or $25 closed headphones picked up at Target is going to be very different than your standard for the same qualities, as you have heard most everything, understand differences even subtle in nature, and have honed listening skills that make even those small difference seem pronounced.
I do, however, get your frustration. I don't think the crazy requests are ever going to stop because they're based on folks' lack of familiarity with what's out there. I do think that we as members can be more helpful by not posting about things we haven't heard personally heard ("Get the AD700s!"....egad...stop it, people), point folks to searches that might provide them with a starting point rather than just listing your favorite gear without explanation, admit if you've only heard one or two headphones if making a recommendation, and, maybe more importantly, tell them that $100 isn't going to give them the perfect rig in sq; tell them that most quality full-sized headphones need an amp, and most need better than a portable amp; that source counts; that there are almost always compromises to be made in sq if you're looking for closed headphones, or portable, or starting out on a budget; that it's sometimes better to save your money to get what you want rather than shooting for immediate gratification; and that it's really okay to enjoy what you have, including ipod earbud and unamped Koss KSC75s. Perfection can be overrated
As regards to those who think telling people to search is bad form, I understand your point, but disagree. This forum has grown to crazy proportions, which is good for the hobby, but not so good if the signal to noise ratio keeps going the wrong direction. Doing research (yes, it takes time) by searching before posting is pretty important to help give new members basic ideas of what's available and narrowing criteria down before asking for recommendations. If you don't want to tell someone to search, that's okay, but maybe provide links to quality posts (reviews, comparisons, etc.), or provide real information rather than creating more blather (i.e., not just parrot recommendations without providing background). At least, it's something to be mindful of, even if not adhered to strictly.