I've always bought Dell - both PCs and laptops - and always bought their 3-year on-site package.
Apart from a replacement keyboard I have never really needed the package for my PCs.
However, I bought an Inspiron laptop for my elder daughter to take to Uni when she started last September and, again, bought the 3-year package which includes accidental damage.
Shortly after starting at Uni, a heavy metal photo frame fell from a shelf directly onto the laptop keyboard and broke off a selection of key - effectively rendering the keyboard useless.
A quick call to Dell's support line and 24 hours later the laptop was up and running again with a brand new complete keyboard having been fitted by a Dell engineer.
The moral of my story? I have great faith in Dell's products but I would still buy the 3-year guarantee in case of that unforeseen event.