I loved watching Federer win Wimbledon again. It was perfect.
I also loved Rosol beating Nadal at Wimbledon, Murray nabbing his first slam, and Janowicz taking down several big names in a row to make the Paris final. I'm very glad Del Potro's back in the top ten, qualified for the WTF, and made it to the semifinals there. There's probably more - it was an exciting year for tennis - but those are the ones I can think of off the top of my head.