The "North Side," in comparison, is the general name given to the northern side of the lake and does not refer to one area in particular. It lacks a central town, and is instead made up of several that are spread out, including Tahoe City, North Star Ski Resort, Incline Village at Diamond Peak, Squaw Valley, Sugar Bowl, and Truckee.
This separation creates a sense of tranquility and more resort-type lodging, whereas the concentration of bars, casinos, and restaurants lends itself to place an emphasis on nightlife in South Lake. As our sis HotelChatter pointed out, the hotels in South Lake range from not-so-pretty to upscale lodging with some of the manliest amenity we've ever seen in the bathroom (seriously).
Bottom line: If you want to party, stay in South Lake.
[Photo: Will McGough; Map: aaccessmaps]