The Drunken Philosopher #4: The "what if" for the night

Time for another random train of thought that crossed my mind in the middle of the night:
Suppose there is another planet on which the ecology was not carbon-based. Since oil is a direct byproduct of cellular decay of carbon-based organisms, what sorts of energy sources might they have come up with in its absence?  In addition, since much of our technology has been driven by the development of plastics (which are synthesized from oil), how differently would their technology have evolved with the use of different materials in their stead?
It also occurs to me that there are many substances and chemicals which exist on our planet, which we do not have an immediate use for.  In the case of an ecology for which the entire fundamental basis of composition for its organisms is vastly different from our own, would it not be fair to assume that some of the chemicals for which we have no use, or which may even be harmful to us, may conversely be essential to some other form of life?
Recall that there are many environs even on our own planet within which organisms from the same roots as ourselves have adapted heightened senses or entirely different senses altogether from what we are capable of using; how stimuli imperceptible to us are perceived by these other organisms is naturally not fully understood by us (as the saying goes, "it's like trying to describe a color to someone who never had sight").  Imagine now the advances we may have been able to have made so much sooner, or even the technology we do have which would be obsolete, if we could even do something as simple as seeing infrared or x-rays; or the music we could create with another few octaves of sound to work with... let alone how we could have developed sociologically with something even more "out there" such as telepathy (some fish have an organ which emits a "frequency" used to communicate with one another to coordinate movements underwater, for example.).  Would a species derived from an entirely different set of circumstances from ours even need to develop any form of communication which could be picked up with our scientists' instruments?
We already know that a culture develops along an entirely different path depending on its environment; what if there was some other sense, the nature of which we are not even capable of grasping the concept of, which allowed a culture to perceive some fundamental fact of science or the universe which we are still struggling to figure out; and how differently a society would develop without the need to create myths and legends to explain phenomena the workings thereof seem beyond logical explanation?  Would a social desire for religion even exist, if we developed a sense with which we could witness the energies of life coalescing and dispersing at every birth and death occurrence?