Aside from some weird thing where Windows gets stuck in a loop while booting if I leave my MP3-player in despite USB not being a priority, my HP Probook is doing a good job. Granted, I never really tested its limits, but I've had it for a year now and use it 5+ hours a day, ever day.
The only laptop I've had that was more reliable, was a Fujitsu Siemens Lifebook way, way back. Probably still works now, but who's going to use a laptop with 64MB RAM?
I also liked my Micropoint Lunar M300. Well, aside from the power supply experimenting with spontanous combustion, that is. I bought Lunar used and despite being several years old it was still quite powerful when I got it. Once I had shoved some extra RAM in there it worked like a dream. It also had an insane amount of cardslots, USB-ports and tons more. I could hook it up to nearly anything. Thanks to that Lunar was a bit of a hero in university. Can't get a presentation to work on a school computer? Lecturer's laptop acting up again? Lunar to the rescue! It was also a pretty nice karaoke machine.
The one thing Lunar could not beat was time and I eventually had to replace it with something faster. The specs of the Fujitsu Siemens Esprimo Mobile I got after that where kinda shitty, but all I needed, so whatever. It was very cheap, but had a lovely screen and keyboard and was surprisingly reliable. Used it for four years and the main reason I replaced it early was to help my aunt and her family. Their laptop could die any moment and they didn't have money for a new one. So I gave it to them. Then a miracle happened and their laptop did not die, but my cousin (that aunt's daughter) dropped hers and they didn't have money for a new one either, so the Esprimo was passed on to them. I saw it a while ago and hardly recognised it. Cookie crumbles and dirt everywhere, both casing and screen covered in scratches... Poor, poor Esprimo ;_;
Oh well, atleast it's still useful...