Extremophilic bacteria are a fascinating resource to study for both scientists and lay persons alike, as their nature can reveal important knowledge that helps to explain other aspects of the world, such as other bacteria, how life started, industrial uses etc.
Extemophilic simply means that it prefers extreme conditions to grow and multiply. Extremophilic bacteria can be found living happily in very high or low temperatures, very high or low pressure, acidity, salinity, low or no oxygen or carbon places or anywhere you wouldn't find other life forms as we know it usually. They can be found deep on the ocean floor, hanging around volcanoes full of sulphur, in hot springs, in dry desert salt pans etc.
Study of extremophilic bacteria helps to understand other life forms, including ourselves.
When the earth was young and hostile elementally, the first life forms - which we ultimately evolved from - would have had to be extremophilic to survive. For those who suspect we started from a meteor with micro-organisms on it, those micro-organisms would have had to survive the freezing oxygen free environment of deep space. Space travel researchers (such as NASA) are very interested in extremophilic bacteria.
Extremophilic bacteria and micro-organisms in general have also been used to solve crimes, particularly murders but also serious thefts etc. It's not just human DNA that can help locate the lost, place people at the scene of the crime, and help pinpoint exact times that events occurred!
Industry also find uses for extremophilic bacteria and their enzymes. They are great for breaking down toxic waste, bringing minerals out of mixed stone, cleaning the "uncleanable", transforming electrical pulses and all sorts of fascinating things. Industrial uses of bacteria is an area that I personally think hasn't been explored nearly enough. They produce a huge variety of enzymes, organic compounds and other by-products. Microbiotechnology is a healthy part of the future, if it receives enough support.
Life in general could not survive without bacteria. Humanity often believes it has "dominion" over life on the planet, but if you removed bacteria, it would die. If you removed us, it would probably bloom into a large bio-diversity and a large biomass. The net weight of bacteria on the planet is far greater then the net weight of humanity. And it is them that ultimately process us. So much for being the top of the food chain. Bacteria is an example of the truth behind the belief "the meek inherit the earth". However, it is not an "Us Or Them" (kill the germs!) attitude that is most productive, it is an "Us And Them" (look what the clever little bacterium can do!) attitude.
Did you know that babies that are kept in extremely sterile environments actually get sicker for longer then ones exposed to more organic life? That's because their immune systems have fewer opportunities to build skills in fighting imbalances in the internal flora and fauna.
I think that bacteria are a great form of life that could be appreciated more with a change of view point from the relevant population. After all they were here first. Go the microscopic life forms!