Home/Consumer Class: including Inspiron, and XPS brands, emphasizing value, performance and expandability:
Inspiron - consumer desktop and notebook systems
XPS - enthusiast and high-performance desktop and notebook systems
Alienware (XPS Extreme) - high-performance gaming systems
Business Class: including OptiPlex, Latitude, and Precision, where the company's advertising emphasizes long life-cycles, reliability and serviceability:
OptiPlex - office desktop computer systems
n Series - desktop and notebook computers shipped with Linux or FreeDOS installed
Vostro - small-business desktop and notebook systems
Latitude - commercially-focused notebooks
Precision - workstation systems and high-performance notebooks. Some of them includes Linux preinstalled. 
PowerEdge - business servers
PowerVault - direct-attach and some network-attached storage (NAS)
PowerConnect - network switches
Dell EMC - storage area networks (SANs)
Peripherals: Dell has also diversified its product line to include peripheral products such as USB keydrives, LCD televisions, and printers.
Dell monitors LCD TVs, plasma TVs and projectors for HDTV and monitors
Services and support:
Dell On Call - extended support services (mainly for the removal of spyware and computer viruses)
Dell Solution Center - extended support services similar to Dell On Call for EMEA customers.
Dell Business Support - a commercial service-contract that provides an industry-certified technician with a lower call-volume than in normal queues; it covers hardware and some software support.
Dell also offers Red Hat and SUSE Linux for servers; as well as "bare-bones" computers without pre-installed software (available on n Series by default and by request on XPS and Inspiron systems) at significantly lower prices. Due to Dell's licensing contract with Microsoft, Dell allegedly cannot offer those systems on their website and customers have to request them explicitly. (Dell does offer those systems on their web site at Dell Precision Open-Source Workstations with Linux
Dell has to ship such systems with a FreeDOS disk included in the box and must issue a so-called "Windows refund" or a merchandise credit after sale of the system at the "regular" retail price.
Axim - PDAs using Microsoft's Windows Mobile (discontinued April 9, 2007)
Dimension - home and "small office, home office" desktop computers (discontinued July 2007; replaced by Inspiron desktops)
Dell Digital Jukebox - MP3 players (discontinued August 2006)
Dell PowerApp - application-based severs