I have experience with a wide range of HP products, and they vary by division and generation.
-
HP calculators have always been tops. I personally have no use for all of the features they provide, and my cheapie Sharp calculators have always been sufficient.
-
HP home computers suck; they may not have always sucked, but every Pavilion I’ve ever seen has been a sack of poor architecture filled with pointless features.
-
I’m not familiar with their laptop line. I believe they’re now selling Compaq laptops, which have a good reputation. I’ve always hated Compaq desktop units, though, almost as much as Packard-Bell.
-
HP professional computers have stood up much better. The minicomputers mentioned by tpayne, as well as the Vectra line, have a well-deserved reputation for excellence.
-
HP lab equipment is now made by the spun-off Agilent. Under both nameplates, equipment and service have been excellent. The Agilent instruments are still run by HP Vectra computers, using Windows NT 4 (someday they’ll switch to a newer implementation, but validation is a long and slow process, and I don’t blame them for dragging their feet).
-
I’ve had mixed luck with printers. The laserjets, especially the 4 series, have been absolute workhorses. Their inkjet printers have left quite a bit to desire, though.