Buy: Murray - he's ready to finally push thru to the other side
sell: Roddick (if he has any stock left to sell);
hold - Birdman
Interesting on Murray. What makes you confident, his results have been nothing spectacular this year, he had a great match against Djokovic but lost, lost conclusively to Federer in Dubai although he did beat Djokovic there - however he couldn't back up that win against Djokovic when he played him again in the final in Miami.
Also, where do you see him breaking through, RG is pretty tightly in the hands of Nadal, with Djokovic and Federer close behind, and both have a lot more clay history to hold their own. Grass - we still have Federer and Nadal who have a strong history of doing well on grass. USopen might be his best chance.. a lot of things can change by then though.
I do agree with hold on Bridman and Tsonga