Lord Pendragon,
My sentiments are similar, but rather than focusing on different cultures, which are by nature more fluid, I'd rather the creators of different races (anthropomorphic or not) spend time developing the nature of a creature. It's a small distinction, but an important one. Culture covers things like language, history, customs, social structure, and mythology. While that's interesting and can give a lot of insight into the nature of various creatures, it can sometimes conceal the essential qualities of a creature too. If you develop a creature's nature, you figure out the most significant aspects of the creature and determine how that affects its psychology and culture.
Let me give you an example: the stereotypical canine-people. The most important traits that stick out (at least to me) about canine-people are: instinctive, keen hearing and sense of smell, pack structure, predatory. The instinctive and predatory elements are perhaps the most important. Canine-people are not rational. At least, not to the extent that they depend upon reason to understand and function in society and the world. Because they are by nature predatorial, canine-people societies tend to be based around the hunt. Individually, canine-people tend to see those outside their pack as potential prey, though not necessarily the type to be killed and eaten. When it comes to getting what or who they want, canine-people are focused, determined, and aggressive.
Canine-people have sharp ears and noses. Their senses of smell and hearing are so acute that they rely on these and body language rather than words to communicate. The bulk of their language lies in the subtleties of scents, posture, and non-verbal sounds. Many tend to approach speech the same way a humanoid would approach a functional, if clumsy, tool. Although canine-people are not much for verbal communication, they have a rich tradition of performance and culinary arts. Though it is likely that they received this bit of culture from other humanoids, they have successfully made it their own. Their music is highly textured and composed of many subtle sounds that are easily missed by those with duller ears. Canine-people theater is simultaneously bold and subtle. Sounds and body language carry the action while scents convey emotion and meaning. Their food, though not always to the taste of other humanoids, has astonishing variety. A modest meal can be a banquet of smells. However, the canine-people who use writing have adapted it to their natures in rather...interesting ways. More than one negotiation has nearly resulted in war simply because a canine-people leader signed a document. (Interpret that how you will).
Canine-people are organized into packs, though a pack can be anything from a handful of individuals to a metropolis. Members in a pack are generally related to each other and are ruled by an alpha, who is the one who is most able to rule by force and/or guile. From the alpha on down, the pack has a clearly defined pecking order. They observe this order when working in any sort of group. Those canine-people who are used to being on top will often try to establish and exert their dominance if they can get away with it. Those more used to being the low man on the totem pole are compliant because they wish to avoid a confrontation they would likely lose. The ones who are accustomed to the middle are subservient towards those above them and domineering (even if affectionately so) to those beneath them. The pack structure of canine-people society is more dynamic than it seems from the outside. Struggles for dominance tend to happen when weaker individuals get stronger, the strong grow weak, or circumstances leave hierarchial vacancies.