I agree with Coz. I don't have a consistent approach to warranties. I have puchased many in the past that I don't use but this is my latest way of thinking.
For me it is an intuitive feeling for risk of breakage vs the cost of replacement vs whether I am likely to upgrade the item before the item breaks.
For a low cost item like a VCR at home that is hardly ever moved, or a tv set - no, I would not get one. I recently missed the time limit on getting an extended warranty on a washer and dryer (which I would have done - large cost replacement) but my GTD system wasn't in place and I didn't get around to it. While the risk of these items breaking soon is not high - the expense of replacing them is.
Car - yes, if I am buying a used car where I can still get an extended warranty, I will do so. I did this for $1,000 a couple of years back and not long after the whole transmission needed replacing - so that paid for itself.
For things like electronics. Laptops and pda's - yes I usually do. The one time I did not, the fan went on my laptop after 1 year and 10 days. I could have just taken it back and got a replacement if I had been smart. Twice now I have purchased a desktop computer and a pda as an open box item and with the money I saved I got the extended warranty. In the case of the desk top computer, I had to take it back the next day because the modem did not work. They just took a brand new computer out of the box and gave it to me as a replacement, no questions asked. With another brand new PDA and a laptop, I got the extended warranties but upgraded them without ever having used the warranty. It seems a waste, but remember you are buying peace of mind, not guarantee that you will need it.
For laptops and PDA's where you are carrying them a lot and they are vulnerable to breakage, I would be very tempted to do so. But the more expensive the unit the more valuable it becomes. For the cheapest PDA's it may not be worth it.
Paul