Few of the major OEMs build any of their notebooks nowadays. HP has barely had any manufacturing facilities since 2000 I think as it sources its notebooks from Compal, Quanta, Inventec, etc. These ODMs also manufactures for Dell, Acer, Sony, Apple, Toshiba and some Lenovos (all brand name OEMs), so don't be surprised if different branded notebooks are all produced in the same factory. When we talk about reliability or durability, it usually comes down to the design and build materials used in the notebooks. Business notebooks from Lenovo (Thinkpad), HP Compaq (nx/nc/nw) and Dell (Latitude, Precision) are known to have undergone rigorous testing procedures that guarantee the reliability and durability of components. Again, these models are regarded as premium models and usually carry a premium over their consumer counterparts.

It's not possible to determine which brand of laptop is the longest lasting because many brands have both premium models and budget ones. The budget models are usually not as durable or reliable as the premium models. If I were to choose, from experience, I'd say Thinkpads, HP's nx/nc/nw and Dell's Latitude/Precision have the best build quality and reliability. Coincidentally, it is no surprise that they're the most popular in the corporate environment. Toshiba's Tecra range used to be really good too, until they began to trim down their offerings with budget models like the A-series.