Best Buy Co. turned in disappointing third-quarter results on Tuesday as the battle to sell flat-panel TVs, MP3s and other hot electronic gadgets has slashed prices and cut into profit. the nation's largest home-electronics retailer said the "very competitive climate" -- plasma and LCD TV prices dropped 25% to 30% -- held its profit to $150 million, or 31 cents a share, up nearly 8% from last year's income of $138 million, or 28 cents a share, but short of Wall Street's expectations. That sent shares lower by 5% to $51.30. The total results were mixed compared with Wall Street's...