Filed under: Analyst upgrades and downgrades , Apple Inc (AAPL) , Chesapeake Energy (CHK) , Starwood Hotels Worldwide (HOT) , Analyst initiations Analyst upgrades: Oppenheimer upgraded shares of National City (NYSE: NCC ) to Outperform from Perform on valuation as they believe the bank is not seeing a mass exodus of depositors. Wachovia upgraded Brookfield Infrastructure (NYSE: BIP ) to Outperform from Market Perform due to what the firm sees as the company's solid cash flow growth outlook, strong balance sheet, and discounted valuation. Baird upgraded Tellabs (NASDAQ: TLAB ) to Outperform from Neutral citing valuation and improving 2009 prospects from 8800, 8600, and 7100 products and better Opex management.. Take-Two (NASDAQ: TTWO ) was upgraded to Outperform from Neutral at Cowen. UBS raised Nortel Networks (NYSE: NT ) to Buy from Neutral. Borg-Warner (NYSE: BWA ) was raised to Buy from Hold at Keybanc. Analyst downgrades: Merriman downgraded shares of TheStreet.com (NASDAQ: TSCM ) and Bankrate (NASDAQ: RATE ) to Neutral from Buy to reflect concerns about display advertising trends and the company's above average exposure to the financial vertical. Baird downgraded Monaco Coach (NYSE: MNC ) to Neutral from Outperform and Thor Industries (NYSE: THO ) and Winnebago Industries (NYSE: WGO) to Underperform from Neutral citing valuations and checks that indicate "dreadful" fundamentals. RBC Capital downgraded Apple (NASDAQ: AAPL ) t ...