Updated from 9:39 a.m. ESTThe flat-screen TV was the hot-ticket item this holiday shopping season and a driving factor in the sales numbers reported Friday by Best Buy ( BBY) and Circuit City ( CC). Both retailers said December same-store sales topped their expectations. Moreover, they signaled that their profits will be relatively in line with forecasts, despite a heated price war that has mangled margins. Best Buy, the larger of the two consumer-electronics chains, said December same-store sales rose 7% from a year ago, driven by strong results in Canada and online. Best Buy said the conversion rate, reflecting the proportion of store customers who make a purchase, also rose. Total sales rose 15% to $6.6 billion and comparable-store sales were particularly strong in flat-screen TVs, video gaming, MP3 players and notebook computers. The company guided to full-year earnings of $2.70 to $2.80 a share, in line with the $2.75 Wall Street estimate. Circuit City posted a 4.2% same-store sales increase and raised its sales guidance for the fiscal year. The company, noting strength in the second half of the month, said total December sales rose 5.9% to $2.10 billion from $1.98 billion. The company had a double-digit same-store sales increase in flat-panel TVs, with single-digit comps growth in sales of digital cameras, audio products and PC hardware. Circuit City now sees domestic fiscal 2007 same-store sales growth of 7% to 8%, up from an earlier view of 6% to 7%. The company projected net sales growth of 9% to 10%, up from its earlier projection of 8% to 9%.