Top 5 sustainability technologies we need

Been doing a bit of thinking about what technologies we really need today. Here is my top 5:

5. Plastic recycling. Most of the waste plastic these days cannot be recycled as high temperatures are required to disinfect it. At high temperatures it breaks down and becomes unusable. With effective recycling we could also reduce our dependence on oil. UPDATE: New Envion Facility Turns Plastic Waste into $10/Barrel Fuel (link). This is heaps cool - recycling plastic into hydrocarbon fuel(which we still need for a long time). They clain that 82% of the plastic is turned into energy.
4. Low temperature heat engine. Let me explain. A lot of engines waste a lot of energy by emitting heat. This applies equally for internal combustion engines and giant steam turbines at power plants. If there was a good way to convert that energy back it would certainly improve the overall efficiency. There are a few things out there (like Stirling engine) but for some reason (an I am sure it's a good one) there isn't widespread use of those. It would be even better if this technology doesn't have any moving parts so it can be used in various portable electronic devices.
3. Energy storage. Batteries are just not going to get that much better or cleaner. Hydrogen is kinda cool but it still doesn't compare with petrol or diesel as far as storing is concerned. You just can't fit the same amount of energy into the same space and weight.
2. Carbon neutral high power engines. This is so we could still have Formula1 cars. Or V8 Supercars. Kidding. We obviously need planes, so there needs to be a way to power those. There is some work being done converting CO₂ into hydrocarbons using either concentrated solar energy or some biochemical process. It would be super cool if those become common use technologies.
1. Clean energy. Doh. There are lots of candidates for this one. Fusion would be nice but we are long away from commercial deployment. Out of solar/wind/tide technologies I especially like this Solar updraft towers. The guy with the letters "PhD" after his name seems to agree with me :) And who says these towers have to be built with concrete? We can just use recycled plastic (and thus solving No 5) attached to lightweight steel frame.