High-definition television can be a joy to watch-but, oh, what a pain to buy. The field is littered with competing technologies and arcane terminology that is meaningless to most consumers. Moreover, it's nearly impossible to define one technical term without invoking two or three others, leaving consumers swimming in an alphanumeric soup of confusion. The manufacturers themselves can't even agree on which of the 18 different digital TV formats truly qualify as "high definition." As a sales support manager for Crutchfield (www.crutchfield.com), a leading online retailer of audio and video systems, you understand the frustration buyers feel; your staff is deluged daily by their questions.