The species concept has been a little awkward and troublesome since the start. In his earlier editions of Systema Naturae, Carl von Linnè considered swedes to be a species with different kinds of swedes as sub-taxa. The simple truth is that differences between organisms are often not clear cut and biologists today are still having trouble defining what a species is - what line you have to cross before you go from one species to another.
People in general are not as weighed down by academic considerations and may have a more clear cut idea of how to define species. As the world is not really managed by biologists, the general perception of species is immensly important to stuff like conservation and less academically hindered definitions may give valuable insight.
So, that was the intro
Now, here's a question for you to answer :
How would you define a species?
Please, don't look up the answer before you write because you won't find one (at least not by consensus, only different ideas) and I'd like to see some unadulterated opinions. No definition is too silly and if yours contains one good idea and one bad one, we can possibly ditch the bad and build on the good!