The biggest development in prole-level electronics during the last year is the new affordability of the DVD player and its sibling tool, the Dolby Digital amp. Thus, our choice for last year's best-budget A/V outlet--the warehouse warhorse Best Buy--retains the title because of its ties to the more reliable manufacturers of low-priced home theater toys: Yamaha, Aiwa, Pioneer, and Nakamichi. At Best Buy, an intro-level DVD player by Toshiba can be taken home for a mere three bills, while Yamaha's tooth-rattling receiver that sports both Dolby Digital and DTS sound can be had for under eight. Although some stingy knob-twiddlers might prefer to peruse the Net or the back pages of Sound & Vision to find their fetish object, a trip to Best Buy affords a quick spin through the DVD racks, not to mention a hungry gaze at the gadget that will eventually make all others extinct: the shockingly vivid HDTV set, which Sony offers in a widescreen Trinitron edition for the best buy of $7,500.