Latitudes and then XPS are the business-class, I think. I have a couple XPS Studios that have long outlived their usefulness. Integrated video, that's why they survived the bad BGA era. ;)
*only if it's a business machine as far as I know. A friend who's working for a company selling those B2B keeps telling me how often they get XPS returned, apparently modern variants just keep failing. Latitudes on the other hand seem almost indestructible.