My wife has has her Toshiba Satellite P15-S429 (P4 3ghz, fx5200go) for just over 4 years now. I've always been a desktop person and would never consider using/owning a laptop as my main computer...ever. She had her laptop serviced under warranty twice (once was for fried mobo/video card) and the second was immediately after she got it back (the wireless was not working/reinstalled correctly). Turn around time for the this debacle was about 6 weeks. And about 6 months ago I had it serviced for a loose power connection on the motherboard (wouldn't charge). After researching how to fix the problem and how it required complete disassembly of the laptop reach the plug, I forked over $150 for someone to do it for me.
I actually just ordered a new hard drive for the laptop since it has been making some louder than usual accessing clicks and I'd rather spend $50 replacing it than her gripes about it when it would die some day. What she uses it for (and me) its a great laptop, but I've learned some good lessons with it. Like Ripley stated, upgradeability outside of ram/hd is not gonna happen. If a major component were to break outside of the hd, you're probably stuck to used parts on ebay for a replacement. *When I did take out the old hard drive to just check the specs on it, I did notice that someone who had serviced it in the past (either Toshiba or the PC place) had bent one of the IDE pins on the HD. Still works fine...
I enjoy the comfort of knowing that I can go into a machine and easily replace a failed or dying part or upgrade to something faster with out trashing the entire system. For her, she doesn't really need it for Facebook/Solitaire/Email/Purse Shopping. High end games are pretty much not gonna happen on that machine, though I've never really tried anything beyond Sims 2 on it (which was a jerky fest). But laptops are sure handy on the long trip to watch movies or surf the web from your hotel room. Even the late night in surfing/email in bed is handy.
She spent about $1900 back in 2004 and it was a pretty high end laptop at the time. She said she'd want another one, but anything beyond $500 is plenty for her. At $2000, I can see buying the extended 3 year or whatever warranty. At $500 laptops, I'd wouldn't think about it.