HP sells its HP and Compaq lines through its Web store and also through retail merchants such as CompUSA and Fry's. And of course through consultants and other third parties.
Online, HP offers for each product line a dozen or so preconfigured systems, many of them fairly fully configured.
Two lines seem most directly targeted at the standard business desktop: the 2000 and the 5000. The 7000 line is the upscale version.
The HP Compaq dx2000 line is "HP's lowest-price business PC family. Great for office productivity applications such as word processors, spreadsheets, and e-mail."
The HP Compaq 5000 line offers "mainstream features and flexibility for a wide range of business needs ... HP's mainstream business PC family with a choice of form factors. Designed to allow users to easily deploy, manage, and transition PCs on their networks." This is the "workhorse" line.
And indeed, the Web site store offers some customization for the 5000 that you can't get on the 2000 line, such as Linux, more choices of box sizes, and 32/64-bit AMD processor and 64-bit OS if you want. This line also comes with a businesslike three-year warranty, compared to the 2000's one-year warranty.
The HP Compaq 7000 line is its "most secure and serviceable with advanced features," which includes some software (HP Client Manager) for the IT department to plan and manage the systems. (This management stuff only starts to become important when the number of PCs your IT department is managing starts to head over the 100-unit mark). There's also some super security tools to prevent viruses and authentication features to prevent unauthorized access. And three box sizes, and the three-year warranty.