Our house has 2 Dells and an HP, from 2001, 2003 and 2007 respectively. Both Dells are still going strong. The first was dropped (about 2 feet), disassembled, un-bent, and reassembled. The second arrived with a faulty LVDS (LCD signal) connection, which Dell promptly fixed after I dealt with their customer support desk and described how very modest pressure on the corner of the screen bezel would cause the entire image to radically change colors. I have nothing to complain about w.r.t. Dell customer service and product support, except that they won't release drivers for newer operating systems (Vista, never mind 7) even though they could. But both laptops are old enough that manuf. quality may be different now.
The HP suffered the NV chipset defect - as, I suspect, do some of the computers mentioned by @windowsmelover above. I knew about the defect before it manifested on that laptop, though, so when it did begin to fail I was able to contact HP support, describe the problems, describe how they were similar to the symptoms caused by the chipset defect, and they promptly offered to repair the laptop and ship both ways at no charge. This, even though the laptop was out of warranty by 6 months. I can't find any fault at all with HP for that. After all, there was no way for them to know in advance that NV had screwed up its chipset manufacturing in a way that would only manifest after a substantial period of time.
To the posters above with faulty HPs, if your equipment suffered the same type of failure and you were treated differently, then I can sympathize with you and would agree that HP owes you a better experience. But I personally cannot find anything wrong with what they did for me.
Windows smart phones are a different story. I had an HP iPAQ 6945. HP barely offered ANY updates on the firmware / software for the phone. And because of a cumulative hanging problem, I had to reboot the thing about once every few days. It seemed that a defect in the installed Outlook software would cause the thing to run out of memory, but HP didn't offer any Outlook updates even though other phone vendors offered updates to their entire platforms (both O/S and apps).