The folks at CNET were surprised to discover that using some Dell laptops can result in electric shocks that "vary in strength from a gentle tingle to a sudden jolt." They also noticed that the shocks occur when connecting peripherals to the laptops. It appears that the offending devices have been isolated to versions that feature a brushed-aluminium finish —namely the XPS M1330 and XPS M1530. Furthermore, they believe the shocks are the result of a power adapter that isn't grounded properly because its 2-prong connector lacks a third pin.
Interestingly enough, Dell's knowledge base acknowledges the problem in an entry entitled "A Tingling Sensation May Be Noticed When Touching Metal Components of Dell Devices Equipped with Two-Prong AC Adapters." However, the entry also states that "the voltage (tingling sensation) does NOT present any risk of injury to the user." Whether that is true or not, getting constant electric shocks from your laptop is, at the very least, annoying as hell. Fortunately, Dell informed CNET that they are willing to replace the two-pin power supplies with a three-pin version if requested to do so. If you are experiencing this problem (and entries on Dell's forums suggest that this issue is not isolated), you may want to hit Dell up for a replacement. [Crave and Dell Forums / Knowledge Base]