If you grow any seedlings, flowers,fruit or veg, the bottles can be used as mini cloches by cutting off the bottom (which can be used as small pot saucers) and placing over the plant, in the ground and in the house and garden. It may be necessary to hold down using a piece of wire coathanger pushed into the soil through the neck of the bottle. PET 1 and 2 bottles are easy to recycle and go on to be re-used as anything from fleece clothing to roadside safety barriers. I don`t have the slightest hesitation about re-using them as water bottles, just rinse the cap well. I think it is a ploy by the mineral water producers to make us buy more. If you make any drinks e.g. elderflower fizz,ginger beer, wine etc. the bottles (water only) are excellent particularly as they will withstand high internal pressure.

I fill a couple up with water and leave them in the freezer - great for using on picnics and trips to the beach as an ice pack.

You can also use the middle- without neck and bottom- for watering your plants without causing erosion.

You can cut the tops of the bottles to use as funnels - I have a whole range of size in my shed for using around the garden.

http://toppertwo.tripod.com/container.htm

http://toppertwo.tripod.com/easy_watering.htm

You can build a Harmonica Microphone using a mineral water bottle and a plastic milk bottle. Obviously, you need some electrical components (£16 worth) and some soldering skills, but it’s the shape that’s the important thing:

http://www.planetharmonica.com/ph2/VE/TMI-micUK.htm

You could fill one or two of them and keep them in the car i case you overheat. We have learnt to do this from experience!

you can make a boat that you can lay on and tan while floating on water.

[…] we have a lot of plastic water bottles, and they are easy enough to recycle/reuse… but what about the screw-on bottle […]

There is a way to make bird deterrents for gardens/allotments with them, involving cutting sections and bending them out like sails so they spin round. I’m not sure exactly how you would go about this though..

You can make a vase out of these bottles.
Check out this link; the last thumbnails display how this vase is done :
http://www.flickr.com/photos/reciclarte/sets/72057594113997025/

PLASTIC BOTTLES WITH THE NEXK REMOVED MAKE GOOD SWEED PROPOGATOR COVERS! Small flowerpots especially, but hey! it depends on the size of your bottle!

I keep an empty 2-litre bottle in the boot of my car, in case I run out of petrol. It’s only happened once, but the plastic bottle was very useful then!