Have you seen the cool Nathan Water bottles? I purchased two from amazon some time ago. (Yes, these are amongst the items they won't ship overseas! We had to divert again..) I'm rarely seen without a water bottle. Not only is water very good for you, I find that I dehydrate quickly and nothing sets off a migraine quicker. So for me I need a water bottle that's not only durable but can hold a large amount of water.
These things come in a variety of size, and I went with the 1 liter size for myself. I also chose pink, in the hopes that my boys would leave them alone. However, should they chose to use them the flip tops (which are very awesome!) are rubbery which means that even if your five year old chews on it, he won't damage it!
I love the clip on it which means taking it on our hikes will be handy. I won't have to fish my oversized water bottle out of the pack because I can clip it to the side. You can supposedly clip them to belt loops too, but I'm so not that brave! I figure with a liter of water I might rip the belt loop right off my pants, but hey who knows.
The best feature? These are BPA free and still affordable. When my last water bottle(s) bit the dust I couldn't find anything! BPA free or otherwise. A few shops carried some aluminum sports bottles that were glazed so your water never came in complete contact with the aluminum, but none of them held enough water. The stainless steel ones I found were not only over the top expensive and not being sold in my town, but the drinking tops weren't sports tops which meant removing the whole lid. Not likely to be spill free, and nothing like sloshing a whole liter of water on yourself while driving down the street.
In America you can purchase these through Amazon and if you buy more then one you get free shipping. Unless they do to you like they did to me, which is to ship them separately thus eliminating your free shipping. Yeah, I wanted to shout about it, but I figure it wasn't worth the international phone call! There may be other sources, but that's where I got mine from.
In Australia (I just found this out last night thanks to Google!) You can buy them on the mainland at Everest Sports. They also do mail orders so you if you don't live in their area you can still purchase them. They are a bit more expensive, but less hassle having to divert through American addresses.
Seriously cool water bottles!