Fire seems to be the element of choice at the moment.
This is your chance to get to know a really exciting bit of gardening kit- the Sheen flame gun. It burns the heart out of weeds and with a bit of practice you wont set fire to a) yourself b) the garden c)anything else. Its powered by paraffin and seems (to the unschooled) to work a bit like a primus stove if anyone remembers what those were. And it looks brilliant- Quickcrop sell them. Not cheap but reckon it will go on for years. (Shameless plug for really good people!)
Failing that, there are gas versions of the above, with a wand which you attach to a gas bottle. I have used the mini version of these, with a small cannister of gas and im not thrilled with the results- and the little tins of gas are not cheap!
And now there are electric weed zappers, of which I know nothing - but i think there is another thread on them somewhere.